126 replies to this topic

[telesonic]

Soundboy121:

 

Fantastic pictures! Goes to show you what this little scope can do.

 

And yes, they are back end heavy. I used tube rings from Scopestuff (I think) but they were a bit too large, so I had to re-felt them with a thicker material. (also Scopestuff felt) I used a Losmandy branded vixen rail to mount the rings.... I don't recall the length off hand, but could get a measurement perhaps tomorrow. I'm pretty sure I bought that from the Sponsor site here *Astronomics.

 

For repainting, it's not too difficult depending on your skill level. I've painted cars (grew up working in a body shop / custom hot rod place) and bike tanks, etc. Yep, I can give you advice - but I'd rather do that via PM.

 

As for my repair/repaint - it's here on the classic forum. I'd rather not spam the link, but if you search my topics, you will see it.

[Soundboy121]

I got my Rings from F L O …. Skywatcher Rings I think they the 160 mm size. And yes it had to be felted up. …I have also a cradle from a Meade 5 inch refractor ,, I prefer the rings to keep weight down

[Soundboy121]

C C and Evo 100 on the Sky Tee 

Attached Thumbnails

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[Drainpipeviewer]

Hi,
the corrector plate of my black Comet Catcher seems to be a bit foggy and I would like to clean it. Does anyone know if it needs to be placed back in exactly the same rotational position or would rotating it be tolarable for the image quality? Thanks.

Edited by Drainpipeviewer, 27 December 2023 - 01:48 PM.

[telesonic]

Hi,
the corrector plate of my black Comet Catcher seems to be a bit foggy and I would like to clean it. Does anyone know if it needs to be placed back in exactly the same rotational position or would rotating it be tolarable for the image quality? Thanks.

 

I think that corrector orientation (outward surface, and rotation) will matter, so I'd do all you can to return it to it's original position after cleaning.

 

The easiest way to do this, is use a couple of small pieces of masking tape - one on the tube, and one on the front cell, right next to the fastening screw. The front corrector on the black scopes, fits inside the OTA tube, and is threaded for the retaining screws , by the way.

 

Remove those screws (not the ones that hold the plastic corrector ring into the cell) and take the whole corrector / cell housing out. If you want to, from there, you can remove the retaining ring (mark the corrector) and clean the corrector plate. I've found it easier to leave the corrector in it's cell, and just clean it there.

 

 

Both of my Comet Catchers have been apart before I got them, so I have no way of knowing what the proper orientation is.... I just put them back as they were.

 

Both correctors also had a bit of fog to them, nothing too bad. I cleaned mine with some distilled water, and a couple of drops of dish soap. Then a final rinse with distilled water only. There are differing ways of cleaning a corrector, and that seems to be the least possible way to damage anything. Mine came out like new.

 

 

Now, this is a question for any other Comet Catcher owners out here on CN:

Do these corrector plates have any sort of alignment mark, or etching to signify what position (in relation to the primary) it should be? I've seen the tiny marks on my C5 and C8 SCT scopes corrector plates - but I'm unaware if the CC ever had a similar marking, if anything at all? I don't recall seeing anything on my first Comet Catcher corrector.... but I wasn't really looking too closely when I had that one apart. Perhaps I need to check that again.

 

Cheers,

T

[Drainpipeviewer]

Thanks a lot for the description how to remove the corrector assembly. I will mark it then with some tape. Hope it will work out well. Not Sure If the fog in the plate matters optically.

[Soundboy121]

make sure you have a lens spanner to take out the corrector and don't put back too tite ....once you get comfortable with taking it apart  flocking and tweaking collimation would be next ... if not enjoy as is ...

[telesonic]

make sure you have a lens spanner to take out the corrector and don't put back too tite ....once you get comfortable with taking it apart  flocking and tweaking collimation would be next ... if not enjoy as is ...

 

Hrmmm.....

Your Orange tube required a lens spanner!? I wasn't aware of that being needed, on the Comet Catcher..... perhaps maybe an Orange tube.

 

I have 2 black tube versions, and the corrector is held into the front of the housing, much like any other SCT corrector is. There is simply a plastic ring with 4 or six screws (phillips head) that thread into the backing plate, no spanner wrench needed. But, I'm only familiar with the black tube versions - can you post a picture of your front cell? ....it might help.

 

But yes, other than that.... easy peasy!

 

 

Thanks a lot for the description how to remove the corrector assembly. I will mark it then with some tape. Hope it will work out well. Not Sure If the fog in the plate matters optically.

 

You are welcome. It's really not hard to do, mostly mentally intimidating... it's a difficult thing to take an optical device apart. If you need help or guidance, you are in the right place.

 

As far as the corrector fog, no.... it won't degrade the views too significantly, but it also wouldn't hurt to clean it, it will only help. These corrector plates are easy to clean, being pretty small in diameter, you can do it in a tiny bathroom, which is what I did for mine. I'd clean the corrector first -  Get rid of anything that might effect the glass in long-term, like mold, pollen..... etc.

 

But before you do that, make sure you read up on it....  have the stuff to do it - distilled water, isopro alcohol, cotton pads, make sure you are triple-checked and ready, before you commit. Mentally prepare yourself, it will take some time.

 

If you do take the corrector out of the cell, I'd advise this:

Make a mark on the edge of the glass, with a pencil or marker notating the front, outside of the corrector, maybe something like this ->

Make a mark near a cell screw - also on the edge of the glass, X for rotational alignment.

 

Both of my corrector plates came out looking like new, they were both fogged, one worse than the other, but after cleaning, clear as glass when done. I don't think that these scopes had any special coatings (or any coating at all) on the corrector plates, at least they don't seem to exhibit that visually - no hues or anything that I can see.

 

I'll be working on one of mine this weekend, so I'll take a closer look for some things I know - corrector plate - wise.

 

Cheers,

T

[Drainpipeviewer]

Today I cleaned the corrector plate of my black Comet Catcher. I realized that after removal of the plastic front ring the corrector plate already came loose while the scope was sitting on the table in horizontal position. I marked the position with an arrow on the side using a pen . The corrector plate didn't look like made of a special fancy type of glass, more like ordinary window glass.  Actually it looked a bit weird, like it had been cut out using a chainsaw resulting in pretty rough edges.

I decided to clean it with a tiny droplet of clear dish soap under running tap water while wiping the surface on both sides. After that I rinsed it with distilled water and the droplets were removed by touching them with a tissue paper. The smallest droplets were removed using a hair dryer. Looks much better now. I put the corrector plate back in and fixed the front ring. Now I have to wait for a clear night and see if anything got worse with positioning of the corrector plate. 

[telesonic]

See, not that difficult of a process to do. I also find that using the tissue paper / paper towel for removing remaining drops of water works very well.

(I like to use blue automotive shop towels - the paper kind, from the parts warehouse - Scott Brand ones, for that. I always keep a roll or two handy.)

 

And yes, I've noticed the same things as you, regarding the corrector plate on my scopes.

 

Both of them had very rough edges, not terrible... but by no means were they smooth like on my C8 or C5 SCT scopes. The ones on the Comet Catcher were very crudely finished edges.

 

I've tried to find a source for it, but I'm pretty sure that it was on a posting somewhere on CN. I recall it mentioning two things specifically:

 

1.) The corrector plates for these were surplus corrector plates, possibly manufactured for Celestron's 5.5 inch Schmidt Camera (from a similar time frame) and were adapted for the Comet Catcher. Whether there is truth to that, I do not know.

 

2.) These corrector plates "appear" flat visually, but there is some method of determining that they are actually slightly curved. To do that, one needs an optical flat... and I can't recall what else.

 

3.) There is (or should be) a specific side facing the primary, due to that curvature. Both 2 and 3 I've seen mention of on here.

 

One of these days, I plan on compiling a bunch of relevant posts and links / topics here on CN regarding the Comet Catcher - mostly for my own amusement, but to also maybe to have a definitive source of information for these particular scopes, being the rarity that they are.

 

That said, well done on the cleaning job!

 

About the only other recommendation that I could advise that you consider is this:

Center Spot your primary mirror! Trust me, it will make collimating the scope much easier. These scopes are kind of tricky, being F3.6.... if it's not very very close to aligned, stars will look terrible.

 

I've used Cat's Eye reflective ones on my primary mirrors. One has the smallest size "Hotstpot" that Jim makes, and my first one was done with a small perforated triangle spot, also from Jim. You don't need fancy tools, but once you add a reflective center spot... it makes things a breeze to align. Well, mostly.

 

 

Cheers, and let us know how it looks once you get out there with it.

Temp

[Soundboy121]

Hrmmm.....

Your Orange tube required a lens spanner!? I wasn't aware of that being needed, on the Comet Catcher..... perhaps maybe an Orange tube.

 

 

I remember  now ..... 1 of my CC had a rattling sound  .... it was a loose Corrector plate ... just had to do a 1/2 turn to tighten

 

adding my 2 cents worth when it comes to collimation on C C , I read it on one of the C C threads here

 

the knob that holds the focuser sled always pushes the sled physically, so it would make sense to find focus with your fave eyepiece, lock it in, then collimate

 

Happy New Year    Clear Skies 

Edited by Soundboy121, 31 December 2023 - 10:46 AM.

[telesonic]

Yep, that is what I do. I lock the focuser, and collimate - that does seem to fix the lateral shift, which there is a bit.

 

I can say though, at least in my experience.... the sled focusers used on these MIGHT require adjustments to them, and it sure doesn't hurt to try that.

 

The sled on my 1'st CC was pretty sloppy,  very sloppy.... actually when I got it. The top of the sled would visually shift, when using the focus knob. I took the whole focuser assembly off of the tube, and inspected it, making note of any adjustment screws - and other things (tiny ball bearings) before tearing in to it.

 

That one works pretty great now, and it was mostly figuring out a few things that helped. There are some reaaaaallly tiny screws, on the side of the sled - adjusting those pretty much fixed it up right. They are tiny, and you need to have a very good jeweler set, but it's doable.

 

That focuser, is probably the biggest gripe with that scope.... I think. I understand the reasonings why, but it's an overly complex mechanism - and has multiple possible failure points, with no replacement parts aside from old salvage.

[clamchip]

I like the idea of using the sled focusing for coarse motion and a helical for fine

but the only helical focuser I can find that screws directly into the 36.4mm female sled hole is a Borg S7315.

Or if you don't mind your eyepiece rotating you can use the economy Borg S4317.

I don't find any of the cheap and cheerful SVBONY helical focusers that will work unless you use an

adapter, 42mm to 36.4mm for $30 and then you might as well just buy the Borg.

Does anybody have a better idea?

 

Robert

[Soundboy121]

I too couldn’t find the SvBony that fit.
I used the Baader 1/14 helical Focuser I think I paid under 55$

[clamchip]

I too couldn’t find the SvBony that fit.
I used the Baader 1/14 helical Focuser I think I paid under 55$

That looks like a great way to go, I might do the same except I really want a non-rotating unit. I suppose it doesn't matter

since I'm not plugging a star diagonal into it.

I like the idea of not having to move the sled. I'm sure collimation changes when the sled runs it's course. Not that it

makes a huge difference at the powers this telescope is made to operate at. Every little thing helps at f/3.6

 

Robert

Edited by clamchip, 05 August 2024 - 12:25 AM.

[clamchip]

I found this Baader unit but the eyepiece rotates with the focusing:

https://agenaastro.c...er-2408195.html

 

Robert

[Soundboy121]

I found this Baader unit but the eyepiece rotates with the focusing:

https://agenaastro.c...er-2408195.html

 

Robert

I use that one and it’s a good match for the sled focuser

[telesonic]

Robert & Soundboy121:

(and all other Comet Catcher folks)

 

SvBony did at some point, have a Vixen 36.4mm threaded helical that will thread directly into the sled on these. I have one of them on my Blue CC (repaint) with the stock sled..... but I bought that helical some years ago. I don't recall where, but it was either Amazon (most likely) or Agena Astro.

 

I've seen this question pop up a few times here, but yes.... they did exist for bit. I'll go through my notes / order history and see if I can figure out a link for you folks, but a simple history search got me nada so far.

 

 

 

As an aside thought, these sled focusers are a bit funky... and there really aren't any parts available for the gears (as far as I'm aware) so it if gets chewed up, you have to start from scratch, which is probably what happened to my CC#2. That one was modified with a 2" helical bolted to the tube - with a block of wood....crudely, but it worked. I changed a few things on it to improve what was already some rather oddly interesting modifications from someone before me... and it ended up being a rather cool "down the rabbit hole" project, and a great scope.

 

Cheers,

T

 

(edited to add a picture of the SvBony 36.4 helical on the stock sled focuser, for reference sake.)

Edited by telesonic, 05 August 2024 - 09:08 PM.

[davidmcgo]

Both the Borg and Svbony focuser I have had a removable ring that had to come off to expose the male M36.4 threads.

 

Dave

[clamchip]

Most all I have found have a 31mm male threaded inlet on the focuser with a step ring adapter to

42mm female.

The baader is a nice looking focuser and short enough to use the 36.4mm extension tube supplied

with the scope. Or to look at it another way too short so it needs the factory supplied extension. 

I would really prefer a non-rotating eyepiece and the Baader rotates the eyepiece when focusing.

I see the SVBony going for under $30 and that's a good deal, if only they still made the 36.4mm. 

 

Robert

[Roger Belveal]

Most all I have found have a 31mm male threaded inlet on the focuser with a step ring adapter to

42mm female.

The baader is a nice looking focuser and short enough to use the 36.4mm extension tube supplied

with the scope. Or to look at it another way too short so it needs the factory supplied extension. 

I would really prefer a non-rotating eyepiece and the Baader rotates the eyepiece when focusing.

I see the SVBony going for under $30 and that's a good deal, if only they still made the 36.4mm. 

 

Robert

Robert. I'm using the SvBony helical with an male to male treaded adapter I got from Agen Astro. They had just got them back in stock...

[orion61]

  I have owned 3 of these tubes since the 1980's. They are decent for Astrophotography, but they had poor optics.

The focusers are horrible and wore out with moderate use. All 3 of mine had bad spherical aberration, none were better than just fair
optically. 
They were good for only one thing that was prime focus astrophotography. When the images were blown up, my C5+ with a focal reducer blew them away.
  I hope there are examples with better optics  out there.
They are nice looking tubes and a great idea, I hope your experience was better than mine. Do a star test at 150X and images turn to mush. Contrast on mine was very poor except for Prime focus wide field Deep space objects..
Thanks for the jog of my memory to the 1980's
Duane 
 

[CHASLX200]

  I have owned 3 of these tubes since the 1980's. They are decent for Astrophotography, but they had poor optics.

The focusers are horrible and wore out with moderate use. All 3 of mine had bad spherical aberration, none were better than just fair
optically. 
They were good for only one thing that was prime focus astrophotography. When the images were blown up, my C5+ with a focal reducer blew them away.
  I hope there are examples with better optics  out there.
They are nice looking tubes and a great idea, I hope your experience was better than mine. Do a star test at 150X and images turn to mush. Contrast on mine was very poor except for Prime focus wide field Deep space objects..
Thanks for the jog of my memory to the 1980's
Duane 
 

Mine was mush city and so bad i got rid of it fast.

[Soundboy121]

Robert. I'm using the SvBony helical with a male to male treaded adapter I got from Agen Astro. They had just got them back in stock….

 

 

which part please sir ?

Edited by Soundboy121, 15 August 2024 - 01:21 PM.

[jgraham]

+1

 

The addition of the helical focuser is like adding a little Moonlite to your Comet Catcher. I have added one to all of the Comet Catchers.

 

Excellent little mod.