20 replies to this topic

[elmiko]

I just purchased the Hyperstar system for my 8" Celestron SCT. When I go to unscrew the secondary knurled ring the whole secondary housing is turning. I know that you don't want this to happen. Just wondering if anyone knows a smart way to hold that thin section of the secondary housing while unscrewing the knurled ring off.? I tried rubber gloves so not to gunk up the corrector plate with my oily fingers. I can't get the knurled ring to loosen without the whole secondary housing from loosening.

Anybody with experience with this.?

[GoFish]

I have some frustrating experience with this, too. 

 

First, what worked for me to get the retainer ring off was to simultaneously pull out and twist the retainer ring. The pulling increases the friction on the inside face of the corrector and might allow you to get it loose. Pushing in and twisting might work, too. Anything that increases the friction between the housing pieces and the glass is your friend. 

 

Second, I fixed the problem by ordering and installing a sorbothane gasket from Starizona. 

[descott12]

I just purchased the Hyperstar system for my 8" Celestron SCT. When I go to unscrew the secondary knurled ring the whole secondary housing is turning. I know that you don't want this to happen. Just wondering if anyone knows a smart way to hold that thin section of the secondary housing while unscrewing the knurled ring off.? I tried rubber gloves so not to gunk up the corrector plate with my oily fingers. I can't get the knurled ring to loosen without the whole secondary housing from loosening.

Anybody with experience with this.?

Hmmm, I haven't had the problem but I will say that the threads on my Hyperstar seemed particularly "soft" and I damaged them the first time I installed it by trying to thread it when it wasn't perfectly aligned. Be careful of that.

I found it best to thread it on when the scope is vertical. It seems to settle  in the best and it threads on easier.

I think you are going to love it. I couldn't live without mine  now.

[elmiko]

I have some frustrating experience with this, too. 

 

First, what worked for me to get the retainer ring off was to simultaneously pull out and twist the retainer ring. The pulling increases the friction on the inside face of the corrector and might allow you to get it loose. Pushing in and twisting might work, too. Anything that increases the friction between the housing pieces and the glass is your friend. 

 

Second, I fixed the problem by ordering and installing a sorbothane gasket from Starizona. 

Yes , first thing, thanks for your input. I have thought of the same technique, just apprehensive in putting too much torque on that thin corrector. It already loosened about a quarter of a turn. That's when I snugged it back .... The secondary housing that is. I was also thinking of replacing the collimation Phillip screws with some Allen head screws. That way, maybe I could hold the secondary from loosening with a Allen wrench in one of the screws. While I loosen the retaining ring.

Good idea??

[GoFish]

I think the corrector is pretty strong as long as you don’t go all gorilla on it. Just pull/push straight and don’t pry on the secondary assembly. 

 

I don’t see how using hex socket screws and Allen wrench will help, but I may be overlooking something obvious. 

 

Maybe you should drive to Tucson, buy the sorbothane gasket, and beg for help 

[elmiko]

I actually live about 2 hours drive from Starizona. My wife and I drove down today and she bought me a early Christmas present! She's so awesome! I've been eyeing the Hyperstar for years now, being that the Celestron 8 SCT had the Faststar secondary and was compatible with it. So I called Dean the owner around 5:45pm but they close at 5:00pm. So I will just call in the morning. He will know exactly what to do. I tried pulling up and unscrewing the retaining ring off, but the housing loosened again.....so I just have to walk away before I cause damage.

Thanks for everyone's help!

[GoFish]

I bought my Hyperstar there in person, too. I needed a new secondary holder because my older C8 OTA was not Fastar-compatible. To my amazement, Dean offered to install the new secondary holder, recenter the corrector, and collimate the secondary for me while I waited. Nice group of folks there!

 

(I have a different C8 that had the same problem as yours, and did the sorbothane upgrade myself). 

[WadeH237]

Starizona should be able to help you.

 

I ended up replacing the secondary housing on my C14 because it was a bit out of spec (the Hyperstar assembly would not quite fit).  The new secondary housing came with a gasket that was a different material than the stock Celestron one, and it much less prone to slipping on the corrector glass.

 

Also, it's important to know that you need to be very careful when you tighten the secondary retaining ring.  You need to stop tightening it immediately when it stops. Do not "snug" it at all, or you may have trouble taking it off again.

[elmiko]

Thanks Wade, yes I will not tighten it up too much. I don't want to go through this again.

[elmiko]

Hmmm, I haven't had the problem but I will say that the threads on my Hyperstar seemed particularly "soft" and I damaged them the first time I installed it by trying to thread it when it wasn't perfectly aligned. Be careful of that.

I found it best to thread it on when the scope is vertical. It seems to settle  in the best and it threads on easier.

I think you are going to love it. I couldn't live without mine  now.

Thanks for the suggestion Dave!

[Don W]

Can't find it just now, but there has been discussion about the allen head screws. The idea is that you put one allen wrench in one of them so that it is in the field of view. It gives you a reference to which screw to turn during collimation. I've been using them for a couple of years.

[elmiko]

Okay, I want to let everyone know that I drove down to Starizona this morning and Dean the owner and Hyperstar super hero fixed everything! He ended up using a pair of pliers that had tape on the jaws so it wouldn't mar the secondary housing and loosened the retaining ring. With a little effort he broke it loose! He then put that new gasket on and cleaned the corrector plate, put it back together, replaced the factory Phillip head screws with some stainless hex head screws I had. And lastly he collimated it with a fiber optic artificial star! Perfection! Concentric circles!

Have it setup ready for first light!!!!!

[WadeH237]

Woo Hoo!

[GoFish]

Okay, I want to let everyone know that I drove down to Starizona this morning and Dean the owner and Hyperstar super hero fixed everything! He ended up using a pair of pliers that had tape on the jaws so it wouldn't mar the secondary housing and loosened the retaining ring. With a little effort he broke it loose! He then put that new gasket on and cleaned the corrector plate, put it back together, replaced the factory Phillip head screws with some stainless hex head screws I had. And lastly he collimated it with a fiber optic artificial star! Perfection! Concentric circles!

Have it setup ready for first light!!!!!

Very jealous of you folks that live within driving distance of a good astro shop. Glad to hear there was a happy ending. 

[elmiko]

Thanks Jim. Well still not a happy ending yet. I'm out right now trying to get my stars looking good. They are blocky. I don't know if it is a spacing thing or not? I use a 57 mm spacing between the sensor and the field flattener when I use my refractor. I don't know if I need that spacing with the Hyperstar or not?

[GoFish]

Don’t you just buy the Hyperstar adapter matched to your camera and forget about it?  I have 2 adapters, one that is matched to ZWO cooled cameras (e.g. ASI294MC Pro) and one that is matched to most ZWO uncooled cameras. 

[tmaestro]

Thanks Jim. Well still not a happy ending yet. I'm out right now trying to get my stars looking good. They are blocky. I don't know if it is a spacing thing or not? I use a 57 mm spacing between the sensor and the field flattener when I use my refractor. I don't know if I need that spacing with the Hyperstar or not?

Yes, the Hyperstar has very specific spacing requirements.  When you buy a Hyperstar, you specify your camera and they include a spacer that fits between the Hyperstar and your camera to get you that perfect spacing.

[elmiko]

Okay, I thought I had it focuser, but I was way off! I used my Batonov mask and got it focuser. Stars look better but are still oblong shaped. I still have to collimate the Hyperstar better. Just wanted to let you know. Steady as she goes!

[elmiko]

I did call and ask about that they said they supplied the correct adapter.

 

Yes, the Hyperstar has very specific spacing requirements.  When you buy a Hyperstar, you specify your camera and they include a spacer that fits between the Hyperstar and your camera to get you that perfect spacing.

[mclewis1]

Mike, It isn't just about being able to come to focus (that's obviously important) but the spacing back to the sensor in the camera is critical for the quality of the field on a Hyperstar. It's more sensitive to this spacing and tilt in the optical path than traditional focal reducer setups.

 

Some folks even with the prescribed camera adapter will fine tune the spacing using mm and sub mm T thread spacing rings. These thin Delrin rings are sandwiched between the camera and adapter and extend the spacing in very small amounts.

 

Are you using any filters?

Edited by mclewis1, 10 November 2019 - 07:52 AM.

[elmiko]

Thanks Mark, I was thinking the same thing. When I called Starizona, they asked me if I was using filter also. I told them I was not at the time, I wanted to be able to see the small stars to get a good focus. They told me that the Hyperstar system is designed for using filters. And that could have caused the spacing issue. Hope that makes sense.

So I modified my B- mask so it will fit over the Hyperstar.... The center hole in the mask was a little too small. So using a Dremel tool I cut little arcs for clearance around all of the collimation screws.