Testing the TK Tar Baby

[Rosemary Ainslie]

The revenge of....

Hello MileHigh,

Are those self portraits?  Those two pictures?  I thought they looked rather 'rabbit' like.  I rather expected you to look somewhat more 'human'.  Are you actually turning into a naked version of  the 'mad hatter'?  Or is there some other point that you're making? 

Sad lack of self esteem would be my opinion - for what it's worth.  Perhaps that's why you're inclined to occupy the upper, upper echelons of our stratosphere.  It puts you out of reach.  But remarkably candid.  Golly.   I never realised you were promoting yourself as a genius.  I wouldn't bother quite frankly.  Clearly you're not.   Any more than am I.  I merely have a functional intelligence.  But unfortunately there's no evidence of it while I continue to post on this thread.  LOL (again laugh out loud - not 'gosh I'm anxious' - because that would be GIA)

Kindest regards,
Rosemary

[TinselKoala]

TK,

Do you have any opinions regarding the fork mount used on the Celestron CPC deluxe series?

I am liking Celestron more and more.  The CPC series has a good reputation. My opinion: they are heavier than they look in the pictures! Also any alt-az mount will suffer in long-exposure AP due to field rotation, but processing software can even handle that to a certain extent. The CPCs can be elevated on a wedge for polar-equatorial use to get rid of field rotation, and the Celestron tripods are good, and you do need the anti-vibration pads for the tripod (sold separately of course.) I've only personally seen them at the SALSA meetings and their owners seem happy with them.  I think they are pretty neat all around, and the Celestron handset software is easy to use and easily flashed to new versions as they issue. Still, for me a German equatorial mount was necessary, and the CGEM is so beautiful and performs so well for the cost that the choice was easy. There are lots of aftermarket upgrades for the CGEM too.
Still... I chose a Meade for my first scope, because portability was very high on my list at the time and the ETX125 fit the quality requirement first, the portability second and the price third. I needed to be able to lug the scope, mount and tripod around on the subway or bus! Now that's not so much of an issue; I can get the whole rig into my old Cavalier and still have room for the dog. Not much else... but there is room for her.

Also, any experience with or info regarding the use of FASTAR optics?

PW

The system is called "Hyperstar" now I think. I've got no personal experience but it was a factor in my choice of the EdgeHD Celestron scope. The Hyperstar adapter itself is pricey and I probably never will be able to afford one now,  but if I ever can ... then that makes the scope something like f/3 with a very wide field of view for AP. It's kind of a hassle to remove the secondary mirror and install the Hyperstar adapter, I understand, and then when you replace the secondary after your imaging session of course you have to re-collimate, but for a former portable Dobs owner that's a routine chore anyway and will bring back fond memories I'm sure.
There probably isn't a need for GPS...you have a cellphone probably and you aren't travelling to random locations every time you set up, are you?... and I've heard that sometimes the GPS gives trouble, both on Meades and Celestrons. It only takes a couple of minutes to manually align anyway.

http://www.celestron.com/astronomy/telescopes/celestron-cpc-deluxe-925-hd.html

Yum.... But consider the weight. The 9.25 Edge HD is as heavy as I want to lift by myself. I don't think I could handle an 11 inch and the 14 definitely no question takes two people to set up. Also... the regular black tube SCTs in the  8"  and  9.25" models have 1.25 inch optical backs and the bigger ones 2 inches. But the EdgeHD uses a 2" optical back also on the 9.25. That was the "sold" point for me, since I'm doing heavy AP much of the time.

ETA: Another thing to be considered is that the CPC mount will only be compatible with the telescope that came with it, mostly. But if you get a  German equatorial (my choice today would be the CGEM DX) you can use any scope on it, so if you later on decide to get a refractor... you have already got the mount for it. The CGEM DX can even hold all three scopes at once with a tandem bar: Refractor, reflector and guidescope.

[TinselKoala]

TK,

Yes, you always give the required data.  I thought your scope shot with your "drawing" on the screen was a scope shot in response to my question regarding the signal at the source, and I saw no supportive settings data.  My intended humor was a bit dry I suppose.

I was referring to the difference in the overall negative value on RA's traces between FIG4 and FIG5.  You'll note that the CH3 trace in FIG5 appears to be more negative than the same trace in FIG3/4.  Possibly as I said, it indicates that the FG ground was at opposite ends of the CSR in the two tests.

The little nuances missing may be 'scope BW related as you say.

PW

The difference in apparent baseline between 4 and 5 may just be a matter of vertical resolution at the different timescales, or it could be a component issue, or the difference in ground position. Since Ainslie has told us that the one diagram is correct (even though the demo wasn't done that way) I've just been using the "wrong" position on the transistor side of the CVR. I might be able to resolve some difference on the scope; I'll check tomorrow.

EDIT: sorry, I got confused there between the "FG ground" and the scope probe reference. I like to keep all probe grounds at the same reference. If one is on one side of the CVR and one is on the other side, there will be current flowing between the two ground leads, even with just a 0.25R, and I don't like that.
I'll do it to check the effects on the trace though, with only a single channel.

The Fig3 and Fig4 shots were evidently taken within moments of each other before anybody fiddled with trace positioning (offset), and so it may be presumed that the experimental setup was the same. Fig5, though... who knows.

[picowatt]

I am liking Celestron more and more.  The CPC series has a good reputation. My opinion: they are heavier than they look in the pictures! Also any alt-az mount will suffer in long-exposure AP due to field rotation, but processing software can even handle that to a certain extent. The CPCs can be elevated on a wedge for polar-equatorial use to get rid of field rotation, and the Celestron tripods are good, and you do need the anti-vibration pads for the tripod (sold separately of course.) I've only personally seen them at the SALSA meetings and their owners seem happy with them.  I think they are pretty neat all around, and the Celestron handset software is easy to use and easily flashed to new versions as they issue. Still, for me a German equatorial mount was necessary, and the CGEM is so beautiful and performs so well for the cost that the choice was easy. There are lots of aftermarket upgrades for the CGEM too.
Still... I chose a Meade for my first scope, because portability was very high on my list at the time and the ETX125 fit the quality requirement first, the portability second and the price third. I needed to be able to lug the scope, mount and tripod around on the subway or bus! Now that's not so much of an issue; I can get the whole rig into my old Cavalier and still have room for the dog. Not much else... but there is room for her.The system is called "Hyperstar" now I think. I've got no personal experience but it was a factor in my choice of the EdgeHD Celestron scope. The Hyperstar adapter itself is pricey and I probably never will be able to afford one now,  but if I ever can ... then that makes the scope something like f/3 with a very wide field of view for AP. It's kind of a hassle to remove the secondary mirror and install the Hyperstar adapter, I understand, and then when you replace the secondary after your imaging session of course you have to re-collimate, but for a former portable Dobs owner that's a routine chore anyway and will bring back fond memories I'm sure.
There probably isn't a need for GPS...you have a cellphone probably and you aren't travelling to random locations every time you set up, are you?... and I've heard that sometimes the GPS gives trouble, both on Meades and Celestrons. It only takes a couple of minutes to manually align anyway.

http://www.celestron.com/astronomy/telescopes/celestron-cpc-deluxe-925-hd.html

Yum.... But consider the weight. The 9.25 Edge HD is as heavy as I want to lift by myself. I don't think I could handle an 11 inch and the 14 definitely no question takes two people to set up. Also... the regular black tube SCTs in the  8"  and  9.25" models have 1.25 inch optical backs and the bigger ones 2 inches. But the EdgeHD uses a 2" optical back also on the 9.25. That was the "sold" point for me, since I'm doing heavy AP much of the time.

ETA: Another thing to be considered is that the CPC mount will only be compatible with the telescope that came with it, mostly. But if you get a  German equatorial (my choice today would be the CGEM DX) you can use any scope on it, so if you later on decide to get a refractor... you have already got the mount for it. The CGEM DX can even hold all three scopes at once with a tandem bar: Refractor, reflector and guidescope.

TK,

The link you posted was just what I was looking at.  But I too was wondering if I would be happier with the GEM.  Possibly go for twin fork and wedge now, and then add the GEM later.  I suspect the fork would be lighter for transport, and then I would have both (eventually).

I think I saw F1.8 listed using the Hyperstar.  That's fast!

PW

[TinselKoala]

That 23 mm eyepiece it comes with is _nice_. Big and heavy, but nice and bright and good flatness out to the edges, retractable eyecup too. With the 9.25 and the 23mm, you get a TFOV just bigger than half a degree... it frames the full moon with a little to spare around the edges. That was another thing about Celestron I liked: the "optical tube assemblies" come complete with dovetail mounting plate, diagonal, finderscope, and that nice eyepiece. Other manufacturers just give you the tube itself if you get the "OTA" without a mount, generally. I was lucky even to get tube rings with the WO, I had to buy the dovetail and diagonal and red dot finder separately and there was no question about eyepieces with the deal... fergeddaboudit.

Here's a shot of Aristarchus I did with the EdgeHD 9.25 and the Celestron NexImage webcam imager, which is roughly about equivalent to a 12 or 15 mm EP. This is the full frame, no cropping or other enlargement, just stacked from a bunch of short exposures and processed with RegiStax and PixInsightLE.