Discovery EQ 8" Reflector

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Discovery EQ 8" Reflector
I bought the telescope after seeing it in Astromart's classifieds. It's a Discovery OTA on a Celestron CG-5 mount. I think it would have been nice if they had made a mark opposite the focuser so it could be properly aligned. The diagonal holder is plastic and prone to having the collimating screws "burrow" into it. This I do not like. Having removed the primary, and secondary, I think Discovery should have done a better job at machining the tube. Some of the screw holes don't line up very well. They were obviously drilled before the metal was formed into a tube. Also, it's got a 2' focuser, which is all metal. The problem is that the toothed track is a little too narrow for the slot in the focuser housing. This causes things to shift a little going from inside to outside focus. Possibly a factory made center spot on the primary would have been nice as well. Overall I am happy with this setup. The things that need "fixing" I can do or have done.

Overall Rating: 7
Weight: 1 (Unreliable Vote)
Date:
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39300

Discovery EQ 8" Reflector
I ordered this scope in July, and been very happy with it. It was well packaged, and assembled. It has a metal sonotube, and comes with two good Plossl eyepieces. The mount is steady, and vibrations damp out quickly. Although UPS roughed up the box quite a bit, it arrived collimated and ready to observe. When I eventually took the scope apart to wash the primary and re-collimate, I found one screw hole that was slightly off, requiring only a little squeeze of the tube while screwing it back in. After that first time I've had no troubles with reassembly. The bonus motor drive was just the icing on the cake...

Overall, this scope offers high quality optics (made in the good old USA) for a very fair price.

Overall Rating: 9
Weight: 1 (Unreliable Vote)
Date:
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39302

Discovery EQ 8" Reflector
The OTA is very nice. Images are bright and clear. The mount however is definitely under sized and can be a pain to operate when swinging the scope around.

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39303

Discovery EQ 8" Reflector
This is a very good scope for the price ($599). However, I had quite a few problems to deal with before I was able to use it effectively. I ordered the scope last July (1999) and although I was told it would take 4-6 weeks to deliver, it actually ended up taking about 3 times this long. As this was immediately after the introduction of the product line it is probably a problem which no longer exists with this scope, although I wonder about new Discovery telescope lines. When the scope finally arrived, the optics were in terrible shape with much dust and even dead bugs on the primary mirror and a flat spot on the edge of the secondary. This occurred even though I had ordered the scope with the premium optics upgrade, which cost approximately an additional $70. I must admit, however, that Bill Larsen (one of the owners) was very accommodating and understanding when I called to complain about the state of the scope I received. I was able to clean off the primary sufficiently to feel that the optics might be workable, but I had considerable difficulty with collimation. It turns out that both sets of endcap/secondary mirror assemblies I tried had adjustment screws which were too short to allow the diagonal mirror to be centered under the focuser. I finally went out to the local hardware store and shelled out about $1 to get four replacement screws which would permit the optics to be properly aligned. I had unfortunately broken the original end cap by trying to bend the integrated spider veins and central hub, to which the secondary mirror attaches, inward in an unsuccessful attempt to get the diagonal centered underneath the focuser. When I explained my predicament to Bill at Discovery, he generously offered to replace the endcap along with the slightly blemished secondary mirror and recheck the primary mirror which had arrived covered with muck, if I sent back the entire OTA to Discovery with everything (including shipping) entirely at their expense (which I did, duh!). He also provided me with an extra counterweight at no charge when I complained that the scope did not quite balance in certain orientations. The only problem with all this was that once I returned the scope, it took forever to get it back, another couple of months.

Therefore, official first light came about 6 months after placing the order, with a set of adjustment screws I was forced to purchase myself, for although I had explained the alignment problem to Discovery in all of its gory detail they had inexplicably returned the scope with the same set of adjustment screws (albeit with a new secondary mirror holder and elliptical flat) which produced the same collimation problem. Using the scope since, after doing fine collimation using bright stars, produces excellent images. I am very pleased with the optics, galaxies and other deep sky objects snap into view under dark skies and star tests reveal neither astigmatism nor any detectable zonal aberrations. The mount appears stable enough and is apparently equivalent to the Orion Sky View Deluxe. The focuser works well for 1 1/4" eyepieces, but unfortunately appears to be inadequate for 2" oculars with the optional adapter ring, which was a waste of $12. The end cap assembly described above, which includes the overly thick and unfortunately integrated spider veins and the attachment hub for the secondary mirror, is a poorly designed piece of work which I would like to replace eventually with thin, individually adjustable spider veins. However, because of the way this piece of hardware has been built onto the scope, I'm not sure that its replacement would in any way be an easy task. One advantage of this monstrosity, I presume, is that it does provide a stable attachment for the secondary mirror holder and perhaps as a consequence of this the scope retains collimation quite well (even being the f/5 system that it is). Even though the integrated spider veins are relatively thick, they don't seem to produce overly objectionable spikes in bright objects. This scope provides beautiful wide field views with my 22mm TV Panoptic and takes the 300X+ magnification of my 6.7mm Meade Ultra-Wide 4000 SP quite well. The 6x30 finder is adequate for field use but quite difficult to align, I added a Telrad to the configuration and am glad I did. The RA drive which was provided with the scope functions adequately, but speed adjustment is rather impractical as you must cycle through all six settings whenever you need to speed up the tracking and it develops some unusual quirks as the batteries run down, although there is no power status available to identify the source of these problems. Also the battery holder easily allows batteries to become unsecured and begin producing the aforementioned quirks, and I intent to wrap a Velcro strap around it eventually to prevent this common occurrence.

Overall, I am now quite happy with the scope after suffering through the problems I did in getting it properly configured for use. I'm even considering possibly purchasing one of the big, new Discovery Truss Tube Dobs. However, I'd very much like to see a review of one of these scopes first and analyze the design details much more than I did prior to purchasing my 8". Although the Discovery technical support team is quite accommodating, their response time history bothers me considerably. I had quite a bit of trouble getting my questions about the 8" answered prior to my purchase and hesitate to go through the same exercise again for another scope purchase. I hope my experience with delays and frustrations was the exception rather than the rule, but the fact that I'm even considering purchasing another scope from them says a lot for the quality of the product.

Overall Rating: 7
Weight: 1 (Unreliable Vote)
Date:
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39304

Discovery EQ 8" Reflector
Astigmatism of the scope: comet trail!!!!!! impossible reach good collimation!!!
doubts about the convenience of the diameter of secondary mirror (1.83 too small). 2.14" should probably have been better. scope work as <7" reflector.

Overall Rating: 3
Weight: 1 (Unreliable Vote)
Date:
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39305

Discovery EQ 8" Reflector
Overall not bad. Mount can be herky-jerky at times and tripod gets stiff at time as well. Focuser sticks in cold weather. Scope did well in star test w/ pyrex upgrade.

Overall Rating: 7
Weight: 1 (Unreliable Vote)
Date:
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39307

Discovery EQ 8" Reflector
I ordered the 8" EQ ($668.00 total) on February 14th. Bill Larsen stated it would ship out that Friday (16th). He stated they7 would email me with the tracking number as soon as it shipped. I waited until the morning of the 19th & no email. So I called & the person I spoke with took my number & stated he would have someone call me back. 7 hours & called again & was told the customer service rep I spoke to left for the day. I had to explain myself all over again & was placed on hold. After about 15 minutes, I was told that they were waiting for some secondaries to be completed as they were out. I was quoted another two days (21st) before the scope would ship. I called on the 22nd & was again told they still did not have any secondaries & the scope would not ship until Monday, 2/26/2001 & I would get the tracking number via email.

On Monday, I still had no email, so I called again & was told they would call me back. They called me on Tuesday morning & gave me the tracking numbers.

I finally received everything on the 5th of March. That night while attempting to laser collimate the mirrors, the secondary holder fell off of its mount as soon as I turned one of the spider collimation screws. Luckily, it did not make contact with the primary. After recovering the secondary mirror from within the tube, I discovered the threaded eyelet on the mounting base had become separated from it. I was able to rig it with a washer & a thin nut placed on the inside of the mount. I called them the next morning and am now waiting for a replacement secondary holder. I can used the scope until then.... Whew... What a mess!

Discovery's customer service needs a little tweaking to say the least. I like the scope however, but I am a newbie so I really can't offer a respectable review yet as I have only used the scope one time. I got respectable views of Jupiter, Saturn & Pleiades, but I now see a flaw in the focuser. When I turn the knob a small amount, the tube shifts about an 8th of an inch which makes for an aggrivating viewing session & even though the collimation checks out, I cannot achieve a crisp focus. Even though I probably should return the scope & get my money back, I like the scope & have ordered a Crayford from another supplier & will swap that out as soon as I get the chance. Right now, I cannot rate Discovery any better that a 5. I give the scope a 6 based on this experience...

(to be continued...)

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Look to the stars, for they are the future of the human race!

Overall Rating: 6
Weight: 1 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39309

Discovery EQ 8" Reflector
This is an addition to the above review...

The Crayford focuser I had purchased came with a too small focus travel (1-7/8"), so I sent it back & purchased the 2"/1.25", all metal focuser from Orion for $109. This focuser is a great replacement even though I had to re-drill the tube. NO MORE BACKLASH!! The focuser that comes with this scope is the same as the focuser on Orion's 8" SVD & the 8" Equatorial from ITE and is GARBAGE. In fact, I believe ALL of these scopes are coming from the same supplier in Taiwan. Discovery claims to figure their own mirrors & I have nothing to dispute that claim. The mirror in my scope is a full 8" in diameter, not 7.9 or whatever. ALL of these scopes sport the EXACT same type of sturdy, all metal construction. The front tube ring & the spider are "die-cast" as one piece so replacing it should prove to be a big pain in the ass. After reading the previous revir\ews on this scope, it appears that Discovery has enlarged the secondary to 2.14" as that is what came with my scope. The finder also came with a diagonal that makes the images right side up, but print is still backwards. the RA motor that comes with this scope tracks well, but batteries do not last long & I have purchased an AC adaptor (12VDC) & car battery adapter. Well, enough said...

Overall Rating: No Vote
Weight: <none>
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39310

Discovery EQ 8" Reflector
I purchased my Discovery 8" EQ f/5 about two years ago. The first thing I did was to sell off the mount and tripod as I felt they were undersized. Now I have it on an old Vixen Polaris mount with wooded tripod and it is considerably more stable. The optics in this Discovery 8' f/5 are very good however there is some coma due to its fast focal ratio. The secondary spider has very wide (about 1/4 inch) veins and I have since replaced it as the secondary spikes were extremely prominent. I also did not like the 2" focuser as it had very rough movement even with over supply of grease they had on it. I have since replaced this focuser with a Moonlite focuser that is smooth as silk. The primary mirror cell had a metal plate over the back of the mirror which I felt inhibits the mirror from aclimating to the outside temperature thus I removed it. I also did not like the push/pull type collimation of the rear cell and modified it with no locking screws and hand tightening knobs to provide easy tool free collimation. All in all I felt the optics are quite good for the price however most of the other components needed modification or replacement to make this scope reach the true potential of its optics.

Overall Rating: 8
Optics:10 Mount:5 Ease of Use:7 Value:8
Weight: 10 (Trustworthy Vote)
Date:
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Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=89815

Discovery EQ 8" Reflector
I bought this scope about 2 yrs ago. It was in stock as a web special on Discovery's web site. I question whether this scope has Discovery's "made in USA" optics in it or if it is just imported from China. The mount is Lin Optics brand as was the RA drive unit. The scope and mount seem typical of the imports so popular now. Optically it is pretty good with no obvious signs of mirror defects on the star tests (very similar) either side of focus. No apparent significant zones, astigmatism or correction problems. Being f/5 coma is a problem in the outer edges of the field. The focuser is pretty high profile requiring it to be racked into the scope tube quite a ways causing some defraction issues. I modified the 1-1/4 in. adaptor that screws into the larger 2 in housing so that it did not hold the EP so far out. I also built a 2 in - 1-1/4 in low profile adaptor to screw into the focuser so that I can reach focus with a camera. The tube is somewhat short putting the focuser very near the open end of the tube resulting in some contrast issues. The secondary spider is built right into the end tube ring (one single cast metal piece) with vanes that are 4-5 MM thick which causes additional defraction issues. I use this scope for viewing and astrophotography (astro photos using a different EQ mount). The mount had some sticky spots in both axis (RA and Dec) but improved after taking it apart and cleaning it up and regreasing with lithium grease instead of the thick kayro syrup used in these mounts. The RA drive supplied is adequate to track stars visually but is not good enough for astrophotos. One has to step through 6 stages of incremental slew rates just to increase the speed momentarily while tracking. There is no reverse control short of pausing the drive. The supplied polar axis alignment scope works ok, but has no adjustment to make sure its aligned with the RA axis. Being an f/5 scope, colimation is somewhat critical. The adjustment screws are philips drive so it is cumberson to try to adjust without moving back and forth from the rear of the scope to the eyepiece. Its easier with a laser collimator which has the view port. The supplied eyepieces were 25MM and 10MM Plossels with the 25 being OK (similar to Orion std Plossel) but the 10 MM only has about a 40 deg field of view. The view in this scope starts getting pretty mushy past 300X even under good seeing conditions; but from 40X to 200X it is pretty sharp. Overall the value for the price paid is reasonable.

Overall Rating: 8
Optics:8 Mount:7 Ease of Use:8 Value:9
Weight: 1 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=263569

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