Posts Made By: Tom Hole

Bob,

Nothing that I know of will give you that with binoviewers. The largest TFOV I can conceive of would be my ST80 with a 400mm focal length with a 1.2x corrector and 24mm Panoptics which gives you 20x at 3.4 deg TFOV (very nice BTW). Nothing else that I can think of would get into that kind of TFOV.

Even in cyclops with a 2" focuser to hold a 31 Nagler, your best TFOV is 6.36 deg at 13x in a 400mm focal length telescope.

Was this question meant for the binocular forum?

Clear skies,

TOm

Well, he's rated now...

http://www.astromart.com/userinfo.asp?uid=31606

Tom

Where are you guys? It was cold last night here in MD but no snow. I love the first snow, and maybe even the second, but then I prefer spring to show up.

Clear skies and warm toes,

Tom

Yeah, those guys with more than 15 5 star ratings scare me every time. Just can't trust a guy that would trade an AP130 Starfire for a 155EDF. That's just craziness!

Clear skies

Tom

David,

My guess is no. My 2.5x powermate does not work as the laser spot is too small on the mirror to cover the center spot donut thingy. My 5x powermate makes a bigger spot and might work, but my 3x barlow works much better. The reason I'm guessing that the 2x powermate won't work is that it is simialr to the 2.5x powermate in that the lens pairs are telecentric (I don't know what that means, but I did stay at a Holiday Inn Express last night . It probably won't make a big spot on the primary as the laser will not diverge as it does with a barlow.

Apogee sells a 2" barlow for $75. Might be considered dirt cheap. I guess it depends on how expensive your dirt is.

Clear skies,

Tom

Peter,

The Apogee HD is probably the best deal right now on Chinese mounts at $159. I just bought a used set of dual drives for it for $80. It's as good as any of the GP clones.

Tom

Joplin,

I'm drooling! Thanks for the pics. I downloaded them all and went through them several times. I am waiting on the thumb screws as well, but hopefully my 1278 will be here soon. Very excited.

Tom

The focuser initially would rack out but not in. Again with the ranting and raving whilst thrashing about on the floor. Turns out, I just needed to adjust the screws a bit here and there and it was working nicely. There is some backlash that I could not get rid of but the motion is very smooth. I ended up mounting the OTA on the mount upside down. The weight of the binoviewers would cause the rack and pinion to get bogged down. This resulted in some ratchety motion. After I turned the OTA so the rack and pinion part was pointed up, the motion was good. Even with the OTA vertical and all that stuff hanging off of it, the focuser held up fine.

The jiggling of the mount prevented any critical evaluation of precise focusing. I am very picky about my focusers, so I will report back later after I get my custom GEM. Hopefully it won't have the shakes.

As I mentioned before, the finder is a non-starter. With the binoviewers in, it is completely unusable. So, I have nothing to report about the stock finder. I just put a Rigel on the OTA and used that.

The stock 1.25" diagonal never made it in the focuser. I used my 2" William Optics diagonal that I bought for the 1278. The WO is one nice diagonal. It held the binoviewers solidly in place during my GEM nightmare. I was very confident in the clamp rings and they held up.

OPTICALS

Haven't heard anyone mention the baffle test. I took the diagonal out and looked into the draw tube with my eye as close as I could get it. could see the entire objective with the draw tube racked all the way in and out. Looks like I got the entire 127mm working for me.

Seeing was a 1.5 out of 10. That meant no star testing. I did take a look at the diffraction rings and couldn't figure out why they all looked the same. Ahhh, no central obstruction. Transparency was very good, and most of the porch lights were out so I did a quick surf. LNEM at zenith of maybe 5ish.

I did most of my viewing with the Denk standard binoviewers, 1.37x 2" OCS and a pair of 24 Panoptics or 9mm Nagler type 6's. That gave me 57x and a 1.2 deg TFOV and 152x.

The very first thing I looked at was Mars. Oh my goodness, what the heck is all that purple? Ahhhh..... Then I focused, and most of it went away. I was still in eq mode, so I was not very happy. I took a look again later after I fixed the dovetail and went to alt/az. Ahhh, much better. I used a pair of 9mm Naglers for 152x. Mars is getting pretty small these days and the seeing was atrocious, so nothing much to report here. I may get up a bit early and take a peek at Saturn and Jupiter.

cont'd

Dale,

You have chosen wisely If the extra weight and bulk of the 10" are not an issue, you will be very, very happy. I say that because I almost crapped me drawers when I saw how big a 10" dob is. I will never forget that moment. I was going over to a nice fellow's house that had a Discovery 10" for sale. I met him in front of his house and we walked around back and when we rounded the corner, there was the 10 incher sitting in the garage. Holy macaroni, Batman! That is huge! Of course, it was replacing my XT4.5, 4.5" dob. so that was quite a leap in size. Now I think nothing of it and think it looks small. I need a bigger one

This is not a scare tactic, just a prep for when that rather large box shows up.

For more info, I would recommend a visit to my web site. Not because I am vane, but because there is a lot of info on these types of dobs (Synta and Guen Sheng) that I have collected over the past few months.

http://www.tomhole.com/Astronomy.htm

Also, the yahoo group:

http://groups.yahoo.com/group/skyquest-telescopes/

A great bunch of folks that are very friendly. You may already be a member.

Then come back and ask a bunch more questions. We seem to get sidetracked here a lot, but there are often a few answers that don't stir up too much controversy.

Clear skies,

Tom

Chester,

I have tried it with a 2.5x powermate and a 5x powermate and it will not work. The way a powermate is designed prevents the laser from diffusing and becoming a large spot. It just shoots right through the powermate. It diffuses a little bit in the 5x powermate, but not enough to use for the barlowed laser method.

Clear skies,

Tom