Posts Made By: Dwight Bogan

Here is my image in Ha of the North America, Mexico and Gulf of Mexico area, This was taken in my light polluted back yard last fall this is the combination of 12 5 min subs. Scope was AP 155 F7 at 5.3 on Mach one Mount with ST10 XE

This was an attempt last year of the Veil with my ST10 XE and AP 155 F7 and F5.2 at the Antennas site 100 miles west of Phoenix Ariz, Because I did not think I was getting good Data I cut the exposure short so this is a Median Combine of 5 luminamce and 1 Red exposure. This fall I hope to do some more of this one.

The Micrometer focusor just comes off, you can replece it if you want or you can add and electric focus as well.

Dwight L Bogan

Celestron already has the Starbrite coatings which is the Celestron version of Meades UHTC. In this case its Meade who is catching up to Celestron.

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Dwight L Bogan

The pointing accuracy of the AP mounts is excellent. As long as your optical axis is orthogonal with the mount you should have no problem acquiring tarkets from one end of the sky to the other. From reading your post I would guess you have orthogonality issues with your SCT optics not coinciding with the main axis or the mount.

To correct this problem you are going to need to lock down the mirror so that it is impossible to flop. Then you are going to have to correct for orthonality and ensure that the main optics are coincident with the axis or the mount. This is all explained in the instruction manuals that came with your mount.

If you don't want to do the suggested modifications to your scope, BTW I negleted to mention your going to focus using an after market outside the tube focusser. Then your going to have to live with this inaccuracy. What you do here is sync with an object or bright star every 20 or so degress of movement and when you cross the meridian or the zenith you will have to resync the mount.

Another solution is get rid of the tube assembly and buy yourself a scope where the optics are locked down and don't move.

How do I know this? I own an AP 900 goto and an AP 155 F7 and I also have a Celestron 9.25 SCT yep even that one mirror flops. With my AP 155 F7 being its a refractor and doing a drift alignment allows me to have extremely accurate pointing with this combo. BTW I can have the mount and scope setup and drift aligned in 1 hour and 10 minutes that is my current record. My goal is trying to get it down to an hour! If I put the SCT optics on the mount. Now the pointing accuracy goes out the window. I've looked into mirror lock downs and mods and so on and i've decided its nothe worth the hassle. My answer was to purchase a AP 10 inch Mak which does not seem to suffer from orthonality issues or mirror flop.

One last little detail. The act of recollimating the secondary can through your optical axis off. SCT's are a real pain!

My recomendation is just live the mirror flop issue and just resync the mount as mentioned above. Its easier :-)

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Dwight L Bogan

> I have an AP F7 92mm refractor and I >am looking for a light weight EQ mount 15-20 lbs.I have a >Tak EM-10 which is too heavy and overkill for this little 6 >lb. scope any suggestion will be helpfull,thanks Jun


Too Heavy and overkill! Seems to me for the AP 92mm F7 the EM-10 should be perfect! The only lighter weight solution would be a Teleview Gibralter mount this is what I use for my Stowaway. Another option would be maybe the EM-2 mount or that Eclipse chaser mount that Takahashi makes but I don't know if they are that much lighter. The Vixen mounts and the Chinese mounts are about the same mass as the EM-10. One solution may be one of the early Celestron Vixen polaris mounts but I have not seen one of those in years but on that very rare occasion they do show up on Astro-martfrom time to time. That mount was lighter and smaller than the EM-10. BTW I use my AP 900 goto when I want to track with my Stowaway.:-)

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Dwight L Bogan

I have to disagree. A quartz mirror dumps it heat much quickly than a Pyrex mirror ever well. If you can aford it the way to go would be Quartz mirror. Should you decide to sell your scope down the Road the Quartz mirror would be plus. I own an AP 10 inch Mak Cass and it has a Quartz Primary. I open the back of the scope to the surrounding air the the scope is ready to opserve in 10 min and I've never had to use the cooling fans at all.

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Dwight L Bogan

If your going to install a new Astro-Physics focuser I would think that would increase the value of the that scope. The older focuser if I'm thinking about the right F12 model that you have had a very basic 2 inch focuser. A new 2.7 inch model would be a definate improvement over the older design. I would go ahead and do it. If your nervous about modifying you own tube maybe Astro-Physics well do it for you.

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Dwight L Bogan

Nope the 110mm is the only 4 inch ED apo scope that he makes and TEC Telescope Engineering Company makes the optics. Williams is not an optics designer nor a glass pusher. What he does is machine work.

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Dwight L Bogan

Well one Astromart seller who is willing to let go of his new 5 inch Burgess claims he wants a smaller scope and is even willing to trade plus cash for a Televue 85 or Takahashi FS-78 or something similiar. Of course good ole fashin greenbacks work too.

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Dwight L Bogan