Jump to content


Photo

My First SCT: A C6!

  • Please log in to reply
100 replies to this topic

#51 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 27 January 2013 - 08:47 PM

Pete,

I think in some applications the loss of aperture for binoviewing is negligible - I'm guessing as I haven't done it yet. Terrestrial spotting would be fine and I'm gonna leap here and say the comfort and efficiency of bino viewing offsets the aperture loss on contrasts on lunar and planetary.

I'm interested in a lot of your results now Mike !

Pete


Well, if the effective aperture of the C6 is reduced to 5" with the binoviewer, you still have the equivalent of a 5" binoviewed. That's not so bad. Even so the C6 plus binoviewer will be easier to take out than a 5" refractor. Of course, if I'm binoviewing I'd much rather have a setup where I can use the entire aperture of the C6 - or most of it.

At the end of his tread, Edz appears to concede that this is possible with the C6, but only after much thought and probably more money. I'd rather do the research first before I put out the money. Ideally, I want to binoview with the Burgess binoviewer I already have, and just purchase the adapter and diagonal to make it possible to use most or all of the C6's aperture. I don't want to buy another binoviewer now. If that's not possible, I'll just monoview. No biggie.

Mike

#52 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 01 February 2013 - 09:47 AM

Yesterday I removed the 6x30 finder and bracket from my C6. I replaced it with an ES 8x50 straight-through illuminated finder. This finder is straight-through, erect-image and non-reversed, so the orientation will match the naked-eye view as well as most any atlas I use.

The bracket for the ES finder has four screws for attachment. The supplied screws were too short for the C6, so I had to find some among my old telescope hardware. Unfortunately, the C6 only has two screw holes for mounting a finder. Well, actually there are two pairs of the holes, one pair on each side of the focuser.

I attached the ES bracket to the C6 OTA with two screws. This seems to be secure and stable enough. I held the C6 with attached ES finder in various positions, moved the OTA around, and the connection appeared secure.

Mike

#53 Rick Woods

Rick Woods

    Voyager 1

  • *****
  • Posts: 14604
  • Joined: 27 Jan 2005
  • Loc: Inner Solar System

Posted 02 February 2013 - 03:13 AM

Mike,
Have you actually used the scope yet? If not, you might want to hold off customizing it until you're sure it's a good one.

#54 t.r.

t.r.

    Skylab

  • *****
  • Posts: 4452
  • Joined: 14 Feb 2008
  • Loc: 1123,6536,5321

Posted 02 February 2013 - 08:49 AM

Even if it isn't, send it back for a replacement...it is worth exchanging until you get a good one...I did!

#55 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 02 February 2013 - 09:19 AM

Rick,

Have you actually used the scope yet? If not, you might want to hold off customizing it until you're sure it's a good one.


No, not yet. It seems that winter weather has come upon us since the C6 was delivered. I need to carry the scope around the side of my building to setup. That's not going to happen while there's snow and ice on the ground. But I might just put it on the porch and test it on Polaris.

Despite what Ralphie Boy said, I'm in no hurry to customize this scope. Besides, I want to see how it performs from the baseline first. The only change I've made is to replace the 6x30 with an ES 8x50 finder, but I can put the old finder back on if I decide to return the scope.

I don't now what non-reversible changes I could make except for maybe flocking the baffle and the interior of the OTA. I'm in no hurry to do that.

I've never returned a scope. Luckily, mine have all been fine so far. Not "excellent" perhaps, but at least decent. I'm not the type who orders a scope, and keeps returning and replacing them until I hit the Chinese scope lottery. Yes, if the scope is clearly a lemon, I will return it.

Winter is not a good time for excellent seeing here - to put it mildly - so I don't know when I'll be able to do a thorough star test. But the daytime collimation check seemed right on. No significant difference on either side of focus.

Mike

#56 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 02 February 2013 - 09:22 AM

t.r.,

Even if it isn't, send it back for a replacement...it is worth exchanging until you get a good one...I did!


How many times did you exchange your C6 until you got an acceptable one?

Mike

#57 t.r.

t.r.

    Skylab

  • *****
  • Posts: 4452
  • Joined: 14 Feb 2008
  • Loc: 1123,6536,5321

Posted 02 February 2013 - 10:55 AM

Oh, just once. The first one I had didn't have equal star test image on either side of focus. Even the the planetary performance seemed just okay, the defocused diffraction pattern told me something was amiss. The first one was the "newer" model, with the nicer dew cap(formed handle in the plastic) with a nicer tube finish and stenciled logo. The second one was the older tab dew cap, duller surface paint and a stickered logo, I kid you not! But when I star tested it and put it on Jupiter, I knew this "Ugly Duckling" was a keeper. I later took it to "Barefoot" Bob Piekel(SCT guru) for testing just to confirm I wasn't imagining its performance. He tested it to close to 1/8 wave slightly overcorrected (1/6 to 1/7th solid)! He said the C6's he has tested have been consistently very good. My first was simply not up to my expectations, it happens. Work with the dealer and exchange...it was painless.

#58 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 02 February 2013 - 12:13 PM

So it seems like your first was a lemon, worse than the usual C6 that comes off the line.

My C6 has a shiny black surface - no sparkly effects, though. "Celestron" is stenciled in orange, and there's a sticker that says "Star Bright XLT." The dew cap has tabs.

The vendor exchanged your newer model for an older one?

Mike

#59 t.r.

t.r.

    Skylab

  • *****
  • Posts: 4452
  • Joined: 14 Feb 2008
  • Loc: 1123,6536,5321

Posted 02 February 2013 - 01:01 PM

I believe this to be the case, it was during the change over with the C6, so they probably had stock of both. IIRC the packaging was the same. I liked the newer lens cover better.

#60 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 02 February 2013 - 01:05 PM

I have a Hubble artificial star that I'll use to test the C6 here in my house, if I can find a line of sight that's long enough to get a half-way decent test. The star is rigged up on a photo tripod, and the C6 is on a Voyager mount. Seems like these artificial stars might be close to useless unless you have a huge house or a back yard with enough space for a good test.
Condo astronomy is a royal PITA! :vomit:

I ought to move to wild wonderful West Virginia! Yahoo! Plenty of space down here - not just what's up there in the wild black yonder! :whee:

Mike

#61 t.r.

t.r.

    Skylab

  • *****
  • Posts: 4452
  • Joined: 14 Feb 2008
  • Loc: 1123,6536,5321

Posted 02 February 2013 - 01:23 PM

The telephone pole glass insulators work very well when its sunny! In addition you can try a silver christmas tree ornament...it actually works too!

#62 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 02 February 2013 - 03:21 PM

No above ground telephone poles in my neighborhood. All the trees are in common areas. Not my property. It would not look too good to see a middle-aged man shimmy up a tree to hang a Christmas ornament. :crazy:

Things are different in Condo World. You really need to think out of the box.

What I might do is set up the artificial star on the front porch. Then I can walk the C6 outside to the back corner of our building, or maybe farther away, sight on the star and check the scope.

Mike

#63 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 02 February 2013 - 08:10 PM

Today I set up the artificial star in my home, as far as possible from the C6. I put my BCO 10mm in the focuser, for 150x, 1x per mm of aperture (p. 17, Star Testing). Of course, since the distance was much less than the minimum 49' suggested by Suiter (p. 91), this resulted in some induced spherical aberration in the defocused star image. Actually, Suiter recommends two to three times this distance, about 100' to 150'.

Other than this SA which was an artifact of the imperfect test conditions, everything looked alright. The image looked smooth, no roughness at all. No obvious zonal problems. The image did look about SA = 1/3 wave, comparing to pictures on p. 193 of Suiter's book. But how much of this was due to having the artificial star about 1/5 of the recommended distance from my C6?

I thought there might be a little astigmatism. Or could the horizontal position of the OTA produce some astigmatism? But I checked this by turning my head. Yep, the angle of elongation turned with my head. After that, I kept my glasses on.

Collimation looked perfect. (I even checked that with my XO 2.5mm, giving 600x, 100x per inch.) I'm in no hurry to replace the little Phillip's head screws with Bob's Knobs.

Unfortunately, it snowed again this evening, and winds gusts are up to 30 mph. So there is no way I should even do an artifical star test outside tonight.

Mike

#64 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10355
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 02 February 2013 - 10:30 PM

Mike ,

Im glad to hear about your star test success. I would gamble strongly the 1/5 distance had a good measure to do with the SA. Im not really star test savy like Eddgie, Norme or some of the other guys. I look for clear stark diffraction patterns, astigmatism and then call it a day. I too have a little astigmatism that is problematic at the lower end power oculars. In the 8" im great withy 20mm oculars or smaller. I keep proising myself that astigmatism corrector that Televe makes but as if yet I havent bothered. Does away with the need for glasses by essentially mounting one to your ocular. They DO have astigmatism corrected contacts but in my experience they reduce contrast and some sharpness as they tend to dry out when you observe.

I know you are going to be so happy with the C6 - and the light transmission is terrific. Doesnt that secondary look like its floating in mid air at times?

The XLT coatings are no joke!!

Pete
Mike you observe from your condo too? It took my years to do this as I hated the lack of privacy. I still get interuptions and on summer night weekends its a nogo as too many back deck partiers and such intrude. Hence I drive to a provate place those times - or grumble and stay in the house.

#65 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 03 February 2013 - 12:18 PM

Pete,

Im glad to hear about your star test success. I would gamble strongly the 1/5 distance had a good measure to do with the SA. Im not really star test savy like Eddgie, Norme or some of the other guys.


Yes, so far so good. I will have to set up the artificial star on my porch, and my C6 about 150' away to get a decent test. I hope I have a clear line of sight here in congested Condo World. Everything looked good except for that SA. My estimate of 1/3 wave was completely based on the SA, which I expected due to the pitifully truncated test distance.

However, the prediction is for snow showers every night until Wednesday. Don't you just love winter astronomy? NO!!!! :mad:

So the next clear night for a test with Polaris will be this Wednesday, also. Luckily I have a clear view of the North Star from my porch. I hope glare from the neighbor's lights won't affect the test. Scotophobes! :p

Winter in Condo World - my definition of Hell for amateur astronomers. :mrevil:

Mike

#66 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10355
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 03 February 2013 - 01:40 PM

Well whats great about winter in condo world is a lot of folks are in with the doors shut and no porch peepers checking in on your business. I find I really really treasure the solitude of the pursuit. I consider fellow amateurs part of that solitude but when I have to do the twenty questions with passerbys and my fav : How much did this cost?" Im really wishing I lived in the country again.

The seeing is whats really lousy about winter. When I did live in the country, often poor seeing had great transparency and so deep sky was on the menu, moon willing. But when my moon-free sky is magnitude 5 its hard flr me to take any deepsky serious at all and so poor seeing just kinda sets the tone.

Im betting those unbearable heatwaves of summer bring you steady seeing though much as it does up here in CT. Then the transparency takes a hit but in mag 5 skys its a shrug.

I wonder if I wouldve taken mag 5 skys more serious had I not had 6.2v skys for so many years first.

Didnt mean to sidetrack - back to the thread focus.

Pete

#67 BigC

BigC

    Gemini

  • *****
  • Posts: 3213
  • Joined: 29 Sep 2010
  • Loc: SE Indiana

Posted 04 February 2013 - 01:26 AM

The telephone pole glass insulators work very well when its sunny! In addition you can try a silver christmas tree ornament...it actually works too!

Now that is something I need to do;if I can just get the ornament well up in the tree!

Local hunters will probably think some crazed bird ,raccoon, or squirrel carried it into the branches.

#68 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 936
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 04 February 2013 - 01:47 AM

I think the C6 is one of the nicest true "Grab and Go" scopes out there. It really doesn't require any noticeable cool down time because the optics are always rock solid sharp and its so small it sets up nice on a small mount like my Vixen StarGuy Alt Az Pro Telescope Mount literally in seconds. Its got plenty of aperture for a few hrs of fun, or an entire night out, and the size is such that its forgiving to the atmospheric conditions vs even a C8 because it doesn't have to punch such a large hole in the sky to be effective. I have an orange tube C6se and its perfect with a 24pan up to about 175x just about every night with my 1.25" TV diagonal and the StarGuy alt az mount. It also makes a nice quick set up solar scope when I wanna catch the sun during my lunch hr at work.

...Ralph

#69 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 04 February 2013 - 07:28 AM

Pete,

Well whats great about winter in condo world is a lot of folks are in with the doors shut and no porch peepers checking in on your business. I find I really really treasure the solitude of the pursuit.


Yes, that is the one good thing about winter here.

I consider fellow amateurs part of that solitude but when I have to do the twenty questions with passerbys and my fav : How much did this cost?"


I always give a low-ball figure. Don't want to tempt them. You never know. But here most passersby just pass by. It's amusing how many give a startled little gasp or jump when they see me sitting outside at night. They're more afraid of me than I ever would be of them. Ha! Ha! Scotophobes! :lol:

Im betting those unbearable heatwaves of summer bring you steady seeing though much as it does up here in CT. Then the transparency takes a hit but in mag 5 skys its a shrug.


I have no trouble with the heat or mosquitoes. Better for me than snow, ice, cold and wind. There are periods of excellent seeing in the summer and fall. The rest of the year is usually mediocre to poor.

Didnt mean to sidetrack - back to the thread focus.


A separate thread on problems and solutions for condo/apartment astronomy is in order. I might start one in the General Observing Forum. :thinking:

Mike

#70 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 06 February 2013 - 10:51 PM

I took out my C6 for a star test this evening. According to CSC, the seeing and transparency were average. I thought the seeing was somewhat better than this, maybe 7/10. I let the scope sit out on my porch for a full hour to acclimate. Then I sighted on Polaris for a star test.

I used three eyepieces in succession for the test: BCO 10 for 150x and 1.0mm exit pupil; XO 5.1 for 294x and 0.5mm exit pupil; XO 2.5 for 600x and 0.3mm exit pupil. As I saw with the artificial star when I was testing in my house, the collimation was right on. For each eyepiece, I tried to set the focuser at about 5 and 10 wavelengths inside and outside focus. I could see no appreciable difference at any setting on either side of focus for any of these three eyepieces. No SA at all as far as I could see. :shrug:

I'm not an expert on star testing, but I made a careful attempt to approximate the wavelength settings as shown in Star Testing. As a double-check, I tried to make sure that for each setting, I was comparing patterns of approximately the same size on each side of focus.

I also noticed that there did not seem to be any mirror shift or focus slip at all on the C6, no matter which way I turned the focus knob! Now, this was a very pleasant surprise after my experience with both of these aggravations on my 90mm Mak. And the temps were in the '20's. The little Mak always has these troubles when it gets that cold outside. But not the C6! In this way it's more like my 6" Mak, which also has rock steady focus.

So I don't think I'll be sending the C6 back for an exchange or refund! I'm satisfied that this scope has at least decent optics, perhaps very good. Is it 1/8 wave? I don't have the expertise to certify that, but it looked pretty good to me.

:grin:
Mike

#71 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 06 February 2013 - 11:12 PM

Since the seeing was decent and the C6 checked out AOK, I thought I ought to carry it around the side of my building for a first light. I was a little surprised that I could carry it down a flight of half-a-dozen steps on my porch, while the OTA was mounted on the Voyager Alt-Az. No problem. This is going to be a great grab-n-go scope!

My first object was Jupiter. I viewed it with the BCO 10 at 150x, then the XO 5.1 at 294x. I could see up to about six bands, the polar regions, and some mottling and uneven edges on the NEB and SEB during moments of steadier seeing. This was an unfiltered view. I'm used to observing Jupiter with a Moon & Sky Glow filter. I bet with the filter I could tease out some more detail.

Three moons were visible. All of them appeared as definite disks, little worlds. I could tell that the one on the east was Ganymede. The disk was obviously larger. Unfortunately, the GRS was not on the visible side of Jupiter while I was outside with the C6.

Next I looked at Sirius. Could I see the Pup? No, not tonight. Maybe on a better night. While I was there, I viewed M41 with an Ultrascopic 35 (43x, 1.1 degrees TFOV, 3.5mm exit pupil). The cluster was nicely framed. The stars looked very nearly sharp across the field. I only needed to focus about half-way between on-axis and edge of field to make all the stars appear nearly pin-points. There must not be much FC or other field aberrations for me to be able to do that. And I'm very sensitive to FC.

I turned to M42. With the XO 5.1 in the focuser for 294x, I could see the E and F stars. E was visible nearly all the time. I could see F for over half the time. The BCO 10 at 150x still showed the E star fairly consistently, but F was only glimpsed now and then.

Not a bad first light for this C6! I think I'll keep it!

:grin:
Mike

#72 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10355
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 07 February 2013 - 07:30 AM

Mike -

This is so good to read - not surprised its a performer for you too, but glad just the same. Now the real showdown Im looking for is a dedicated 6" Celestron versus the 6" iOptron Mak.

That's gonna be good!


Pete

#73 bilgebay

bilgebay

    Skylab

  • *****
  • Moderators
  • Posts: 4196
  • Joined: 06 Nov 2008
  • Loc: Turkiye - Istanbul and Marmaris

Posted 07 February 2013 - 07:36 AM

Very good news Mike. Enjoy that little gem. Make sure you have a Telrad on it! :lol:

#74 t.r.

t.r.

    Skylab

  • *****
  • Posts: 4452
  • Joined: 14 Feb 2008
  • Loc: 1123,6536,5321

Posted 07 February 2013 - 08:04 AM

Jeez Mike...you've already surpassed my C6 Jupiter observations with 294x! The best I have attained so far is around 175-200x. If you got that out of it and liked the image, I have no doubt it's in the 1/8th range. I think you can breathe easy and Enjoy!

#75 Sarkikos

Sarkikos

    Hubble

  • *****
  • Posts: 16731
  • Joined: 18 Dec 2007
  • Loc: Per sylvam ad astra

Posted 07 February 2013 - 08:39 AM

Pete,

This is so good to read - not surprised its a performer for you too, but glad just the same. Now the real showdown Im looking for is a dedicated 6" Celestron versus the 6" iOptron Mak.

That's gonna be good!


Yes, I was sweating bullets worrying if I would have the opportunity to do a star test on the C6 before the time expired in which I could return it. The seeing is usually pretty poor here in winter. I guess that's something we should consider before we order a scope this time of year! If the seeing hadn't been steady last night, I was going to set up the artificial star. I'm happy now that I know the collimation is dead on and the optics are at least 1/4 wave, and probably a lot better than that.

I don't know when I'll get to do a comparo between the C6 and my 6" Mak. This weekend I'm taking my 10" to a dark site. I ought to take the two Cats there sometime for a good comparo, but not this New Moon. I could do it here by the house, but I actually feel more relaxed and can do more when I'm in that field in the middle of the woods at the dark site.

The Mak's not an iOptron, but a Bosma f/12 Rumak. Judging from previous views of the star pattern in the Mak, it is at least diffraction limited. I ought to do another star test on that scope, too.

Mike






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics