Posts Made By: Dave Sewell

Hello all, has anyone seen this paint STILL available in the stores, or has Krylon discontinued it? All that I find on the shelves now is "regular" Krylon flat black spray. Don't really know what the difference is, but for home made optical projects, I always appreciated the light absorbing properties of the "ultra" flat black. I've used this paint many-a-times for a lot of projects and I'll be disapointed if it's been discontinued - D'OH! Dave Sewell

Seeing this effect through my 8 inch Dob, but the primary mirror does appear in need of a cleaning - pretty badly actually. Could this be due to a dirty mirror? I've tried various different eyepieces and even rotated the eyepiece while viewing and the glow remains stationary (no movement of glow rotating with eyepiece) - so I'm assuming the glow is caused by the mirrors. I do plan on cleaning them, and I'm aware that a dirty mirror will cause a dimming of the image, but has anyone else seen a glow when viewing with dirty mirrors? The glow is subtle and I'm seeing it regardless of the magnifying power used. This scope was purchased new by me in 1998 and I've only cleaned the mirrors once before as far as I remember. Coatings still look good to me - just a very noticeable coating of dust, pollen, or whatever when doing the dreaded flashlight test. Thanks for any input. Dave Sewell

Hello Michael, I have sent my C8 optical tube in to them for a cleaning before, BUT - the last time I did this was in 1998. So I can't really speak for the current regime. A couple of times since then, I've CAREFULLY cleaned the outside of my corrector plate myself without any problems - but, not as well as when Celestron did it. I will say that they did an excellent job - the optics looked brand new afterwards. I can say the same about TeleVue as well - EXCELLENT work! However, the turnaround time wasn't nearly that long and the price was considerably less. If I recall, maybe 100 bucks back then plus the shipping and I had the scope returned in about a months time. If it's just the front surface of your corrector that needs cleaning, you could learn to do it yourself and save some BIG bucks. If an internal cleaning is needed, I'd bite the bullet and send it to them. Last time I sent mine in, I complained about the quality of the star test, and they "rematched my corrector" (no charge) and I ended up with noticeably sharper views, but still not a perfect star test - just MUCH better than before. Hopefully, you still have your original shipping boxes, which makes for a safer journey back to them if you decide to go for it. Dave Sewell

Hello all - my optometrist has told me that I've got some astigmatism, but nothing serious enough to change my perscription for. My question is - would any astigmatism present in my own eyes possibly give me a false positive whenever I star test telescopes? I guess I could try rotating my head, while examining the out of focus diffraction rings to confirm the source. But first, I just wanted to know if it would even show up in the inside/outside of focus patterns. I realize that in focus, the stars might appear slightly cross-like in my case. I haven't had the chance to check this out yet through a telescope, but the other night, I did defocus my binoculars (of known excellent optical quality) while looking at Sirius, and the patterns did appear slightly oval, and flipped 90 degrees when going from inside of focus to outside of focus. Can someone with astigmatism out there clarify my question? Thanks so much - Dave

Dave, I own 9 telescopes too! Anyway, I once got the chance to prove a point similar to this first hand at a dark sky star party. A fellow there believed a 4 inch apo. refractor was the only way to go. (I think he was saving his money for one.) At the time I had both my 4 inch Genesis SDF refractor and my 8 inch f/6 Dob set up. I aimed both scopes at the same deep sky object (M11) and invited him to compare the views. He was shocked at the difference of the views these two scopes provided. The 8 inch blew away the 4 inch and this was against a scope which is optimized for deep sky viewing with its f/5.4 flat field of view. In this case the fellow was enlightened to buy a bigger reflector and save some serious money as well. In a contest verses a Mak Cas its even less of a contest for deep sky with its narrower field of view. Convince your friend to buy the Dob and maybe later in the future get the Mak Cas. This is how we ended up with 9 scopes each - there is no scope that can do it all. (Although I hate to admit it but it I'm sure it takes LESS than 9 scopes to do it all!) Take care, Dave Sewell

Hello Joseph, The perfect exposure for this eclipse with your set up should be about 2 to 4 seconds during totality. That's if this eclipse is similar in brightness to last Novembers' eclipse. I use a C8 with a reducer corrector and the same E200 slide film. Always bracket your exposure times a few seconds for best results. Good luck, Dave Sewell

Hello Alfred, I bought one of these 8 inch Star Hoppers back in 1998 and still own the scope today. I like the single stalk secondary holder better than the conventional four vane holder myself. There is much less diffraction caused by the single thick stalk than in a four vane system. At least this is my opinion when comparing the views to other 8 inch Newts. Make sure you star test the mirror before buying as all Star Hoppers were not created equal as far as optical quality goes. I lucked out and got a very good one. Also, with mine, I never had to bend the thick stalk to achieve proper collimation. The scope,once collimated, holds alignment very nicely. The new Chinese built Star Hoppers have a lot of problems with the movement of their Dobsonian mounts as I got test two of them first hand. Good luck with the scope. Dave Sewell

Hello Jon, I've got the 8 inch model of that scope which I purchased back in 1998. I believe I spoke to Discovery a few years ago about these scopes and if my memory serves me correct, they said that they only produced mirrors for the larger versions of those scopes. The 6 & 8 inch mirrors were actually manufactured by Celestron. Luckily, the mirror in mine is extremely good - maybe not Zambuto good - but good enough to show fantastic planetary details on Mars, Jupiter and Saturn when they're well placed in moments of good seeing. While some folks didn't like the thick single vane secondary holder, I very much like that feature of my scope - no spikes shooting out of Jupiter or stars during viewing. The 8 inch tube is extra bulky, but tube currents aren't much of a problem with the design. I also like the extra tube length up at the eyepiece end as it provides additional baffling - but that sucker still fits in my car but just barely. I modified mine with ebony star on the azimuth and lined the inside of the tube with flocking paper. Good luck with the scopes - hopefully you got good mirrors as all Star Hoppers were not created equal as far as optical quality goes. I don't even want to think about it when it comes time to yank that mirror out when its time to realuminize. I do not know how bad it's going to be removing the mirror and reattaching it. Dave Sewell

Tim, Check your message box for instuctions on how I successfully collimated my AT-1010. Thanks, Dave Sewell

Regarding the the TeleVue 85, I bought a factory fresh brand new model at the beginning of this year after wanting one since they were introduced back in 1998. The price had always set me back, but FINALLY "bit the bullet" after working some decent overtime. I believe that you get what you pay for in this life, and after owning this scope and comparing it to several other apos in that size class (including the bargin import apos), the 85 always seems to display the most perfect IN FOCUS classic diffraction disk and ring during good seeing. It shows the least amount of scattered light and absolutely perfect collimation. Not saying some of the others weren't any good (most are excellent for the money), I'm just saying if you're critically examining the tightness and crispness of the in focus stars at high power, the 85 wins. Stangely enough, the other scopes displayed nearly identical inside and outside of focus diffraction patterns - VERY similar to the 85. I wasn't a fan of the triplet designs because of cool down issues during very cold outdoor temperatures. The doublet design suits me just fine with its use of less glass and for me, the color correction is satisfying. The tiny little hints of blue surrounding only the very brightest stars and Venus during viewing doesn't bother me one bit. EVERYTHING else I view through the 85 appears color free to my eyes. Thanks for the review Michael. Dave Sewell