10268 replies to this topic

[clamchip]

It doesn't look like it was ever glued, and it is firmly in place, I'll keep an eye on it.

What amazes me is collimation is fine. I just checked it with a glint across the valley.

The scope resolves the Perforated Thingy no problem.

I noticed reflection from the inside wall of the primary baffle tube. This would probably

go unnoticed for astronomy but because I do a lot of daytime I will make a flock paper

tube and slide it in there to eliminate any and all reflection. Thankfully the spot baffle

has no contrast robbing reflection, this reflection is hard to kill.

Something else that should be done is block this big hole I'm pointing at with my red arrow.

This is a passage way for bugs and dust to enter the control box and from there the

optical tube itself.  I pushed a piece of foam in there to prevent disaster.

Robert

 

[deSitter]

It doesn't look like it was ever glued, and it is firmly in place, I'll keep an eye on it.

What amazes me is collimation is fine. I just checked it with a glint across the valley.

The scope resolves the Perforated Thingy no problem.

I noticed reflection from the inside wall of the primary baffle tube. This would probably

go unnoticed for astronomy but because I do a lot of daytime I will make a flock paper

tube and slide it in there to eliminate any and all reflection. Thankfully the spot baffle

has no contrast robbing reflection, this reflection is hard to kill.

Something else that should be done is block this big hole I'm pointing at with my red arrow.

This is a passage way for bugs and dust to enter the control box and from there the

optical tube itself.  I pushed a piece of foam in there to prevent disaster.

Robert

 

IMG_3324.JPG

IMG_3327.JPG

IMG_3332.JPG

 

Yes that gap is really hard to understand. It allows light in as well. I did the same trick on my 3 ETXes.

 

-drl

[icomet]

Clear Skies. 

Attached Thumbnails

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[clamchip]

My wife put some new sheets on our bed that remind me of fiberglass

insulation, sorry honey! 

I guess it was about 3:00 I could no longer sleep but I need my sleep so I didn't

get up, I filled my mind with telescopes hoping to doze off.

When I finally did rise at 6:30 sharp only one thing was on my mind and that was

to get out my C8 for observing. This is all I thought about while laying there. 

Today I'm going thru my C8 making sure it doesn't need anything and it will be

my main observing telescope for a while.

Isn't it odd, just like that, "The Changing of the Telescopes" it just happens to me

like that, a completely new instrument. Something will set me off, this time it is

aperture but I don't want to give up my seated observing. My C8 seemed like 

the natural choice.

 

Robert

Edited by clamchip, 10 May 2025 - 03:57 PM.

[deSitter]

Clear Skies. 

 

Lenovo ThinkScope!

 

-drl

[cavedweller]

Lenovo ThinkScope!

 

-drl

 

[deSitter]

ThinkPad.JPG

 

Still using a W520 Icomet, your scope is magnificent!

 

-drl

[clamchip]

My wife put some new sheets on our bed that remind me of fiberglass

insulation, sorry honey! 

I guess it was about 3:00 I could no longer sleep but I need my sleep so I didn't

get up, I filled my mind with telescopes hoping to doze off.

When I finally did rise at 6:30 sharp only one thing was on my mind and that was

to get out my C8 for observing. This is all I thought about while laying there. 

Today I'm going thru my C8 making sure it doesn't need anything and it will be

my main observing telescope for a while.

Isn't it odd, just like that, "The Changing of the Telescopes" it just happens to me

like that, a completely new instrument. Something will set me off, this time it is

aperture but I don't want to give up my seated observing. My C8 seemed like 

the natural choice.

 

Robert

All serviced and a voyage around the valley today. Aperture really makes the Perforated Thingy pop.

This 1975 orange tube has many configurations, here is my fast jaunt package. Unistar altazimuth, red dot, and external focuser.

The reason I have a dovetail bar on both sides is so my tube doesn't bend like a banana from uneven expansion and contraction.

Robert

 

[Cavs56]

I finally had a semi-clear night and got to spend some time with my 4 inch 15.5 Jaegers build. Optics are excellent and I liked the Criterion mount, very smooth. I had it on a pier I built using the Criterion Dynamax legs. It was not sufficient a 10 to 15 mph breeze was moving the telescope. Not much but I would prefer zero. I had the old pier from the Criterion so I mated it to a Meade field tripod I had. Should be much better I can also adjust the height now. I used a piece of round aluminum stock. Drilled three holes to mount it on the tripod then drilled and tapped three more through the pier. I like it. I will have to get three moving skates for the tripod it’s heavy.

The new tripod with pier is excellent no movement at all. The mount is so smooth just push pull. Did not track. I replaced the cork in the drive, then ran it for an hour. It was slipping. Adjusted the screws a half turn each and is tracking correctly. 

[ryanr256]

The stability of the tripod for the Edmund 4 inch refractor has concerned me from the time I received it. The speader bars were bent, the rivet connection to the legs was loose and the central connecting hardware were missing. I tried straightening the spreader bars but the instability remained.

 

This is my prototype of a simple tripod tray I made from some scrap plywood and square dowel rod. I realize this limits the height adjustability of the mount, but it makes the tripod very stable.

 

 

 

 

[ryanr256]

This is the connection point.

 

[ryanr256]

And, here is the full body shot.

 

[cavedweller]

I discovered this with the CI-700 tripod extension. Adding a few inches between the legs and mount head produced a flexure I could not tighten up. I did not notice it much with the C6R, but the 178 was wobbling 30 seconds after every touch. 

I took another look at the CI-700 tripod and pier extension and believe that part of the instability is the plastic leg spreader. Not only the plastic flexing, but a genuine fear of the plastic breaking if the center bolt is tightened more. This is a candidate for a round aluminum plate (3/8”?) spreader that can also hold eyepieces.

 

[CHASLX200]

I took another look at the CI-700 tripod and pier extension and believe that part of the instability is the plastic leg spreader. Not only the plastic flexing, but a genuine fear of the plastic breaking if the center bolt is tightened more. This is a candidate for a round aluminum plate (3/8”?) spreader that can also hold eyepieces.

 

Spreader Cropped.jpeg

My CI700's were  not worth a hoot.

Edited by CHASLX200, 11 May 2025 - 04:53 PM.

[CCD-Freak]

My CI-700 has been wonderful.  I tighten the spreader fairly tightly and it has never broken.   I also use a CI-700 tripod for my iOptron GEM45 mount.

 

 

 

[CCD-Freak]

GEM45 on a CI-700 tripod.  The white shelf sits on top of the spreader. 

 

Edited by CCD-Freak, 11 May 2025 - 05:20 PM.

[CCD-Freak]

I even have a shortened CI-700 tripod for the CI-700 mount.  (^8

 

 

 

[clamchip]

Today I had a chance to work on my new C90. 

It was a bit major actually. What I think happened is someone shot some compressed air up

the baffle tube and misted the secondary with oil. 

I get really nervous cleaning secondary's like this one with a spot and a cemented on baffle.

You need to prepare yourself, is what I do. And go at it like a surgeon. Give it 100% of your body

and mind and things usually come out OK.

I cleaned and greased the thread for the barrel style focuser. The whole front of the telescope

rotates like a camera lens. Use Mobil 1 for this, it's perfect for it. And make sure you remove all

trace of the old grease.

Robert

 

Edited by clamchip, 11 May 2025 - 07:57 PM.

[clamchip]

I didn't want to DPAC my new C90 but I did anyway and what I saw this morning was quite impressive.

Dead straight jail bars and perfectly smooth. No machining artifacts, no zones, free of anything on the surfaces. 

To see this at f/11 means Celestron must have aspherized the optics and really polished things well. It's no wonder

the C90 was so expensive when new. This C90 is serial number 99056.

This is not the first time I have tested a orange C90, serial number 913908 tested perfect too. Being an Astro

I could date it by the drive motor date 11-80. When purchased this C90 it was severely out of collimation. I corrected it

by replacing the three plug screws in the rear cell with screws long enough to push the primary into collimation.

I also owned spotter model serial 911440 which I never tested  but it was extremely nice at the eyepiece. I no longer own

these two and I wasn't looking for another because I'm not a barrel focuser type guy. My new 99056 came with a ETX-90

I just bought.

What a little sweet potato these C90's are. Just make sure the collimation is good and the focuser thread is full of

grease to prevent shift in the optics when focusing.

Robert

 

[kansas skies]

I didn't want to DPAC my new C90 but I did anyway and what I saw this morning was quite impressive.

Dead straight jail bars and perfectly smooth. No machining artifacts, no zones, free of anything on the surfaces. 

To see this at f/11 means Celestron must have aspherized the optics and really polished things well. It's no wonder

the C90 was so expensive when new. This C90 is serial number 99056.

This is not the first time I have tested a orange C90, serial number 913908 tested perfect too. Being an Astro

I could date it by the drive motor date 11-80. When purchased this C90 it was severely out of collimation. I corrected it

by replacing the three plug screws in the rear cell with screws long enough to push the primary into collimation.

I also owned spotter model serial 911440 which I never tested  but it was extremely nice at the eyepiece. I no longer own

these two and I wasn't looking for another because I'm not a barrel focuser type guy. My new 99056 came with a ETX-90

I just bought.

What a little sweet potato these C90's are. Just make sure the collimation is good and the focuser thread is full of

grease to prevent shift in the optics when focusing.

Robert

 

I've always been impressed with the optics in these little scopes as well, but as you mentioned, they generally suffer from collimation issues. Currently, I own two. One is an astro version with close to perfect factory collimation (a real rarity). The other is a like new spotter version that is horribly out of collimation. I also have the optics from a third, which I removed from a cosmetically damaged scope with the thought that someday I might build into a new OTA. As for the spotting scope with poor collimation, since I now have time due to my recent retirement, and once my back heals to the point I can actually do something, I intend to perform the rather tedious collimation process I described in post 332 of the following LINK.

 

I've since parted ways with the C90 that I described in that post, but up to that time, it continued to maintain collimation quite well.

 

As for my current pair of C90's, I have no intention of letting them get away. They're just too danged cute.

 

Bill

[clamchip]

My new C90 has made it outside and I fitted it for observing. I should add a finder.

This C90 didn't come with any mounting, it is on my Unistar for now.

It didn't come with any eyepieces ether, so I'm using a hybrid prism and my 1.25" eyepieces.

The hybrid prism diagonal is a good choice because you will not be far away from optimum

mirror separation.

Robert 

 

 

 

[clamchip]

I would like to do some observing with my Cave Cassegrain. With the mild

temps I can use high power. There is no low power, the focal length is 4000mm.

I vividly remember I want casters with brakes next time I use this scope, which

is now, so I'll pick them up tomorrow.

I have been using my Cave optical tube on my Star-Liner mount so I can roll it

out onto the driveway in one piece. The Cave on it's Cave mount will not fit thru

my doorway. 

I like these Harbor Freight  4" inch jobs. I have them on a mount and they have

held up fine and have good strong easy to use brakes, the one on the left in my

photo. 

I included a photo of my kit. It's a little short and I have an adjustable observing

chair that helps with that and I eat plenty of fatty foods to keep my neck joints

lubricated.

This marvelous instrument would not get used at all if didn't do something, and

being too short I can at least use it. 

Robert

 

Edited by clamchip, 13 May 2025 - 08:20 PM.

[CHASLX200]

I need some wheels like that for my TV stand.  Salt and sewer water did mine in.

[cavedweller]

I've got those same ones on my Meade RG. They treaded into the leveler holes, so now I don't have levelers.

[Cavs56]

I have those on my 826. Same thing screwed right into the leveler holes. I only use it on a level driveway. Huge improvement over the 3 inch non locking on my Criterion.