Is there a safety mechanism (attaching DSLR to celestron SC tube)?

[Sedna]

Hi all, so I recently purchased this telescope, a Celestron SC tube on a VX mount. My wife has a DSLR and we were setting everything up last night using the t-ring adapter that I bought for her camera (a Canon). We were successfully able to get the camera on the scope, just as shown in this video. However, my wife was a bit horrified that the only thing holding the DSLR in place are the two screws that are tightened. This is the same mechanism that holds the eyepiece in place of course, but the camera is so much heavier, so this seems a bit precarious. She is especially concerned about me having the camera attached for a long time in the dark, where I might not see if it starts to slide. Is there no extra safety mechanism, or something that can lock in place to make sure the camera doesn't slide? Thanks all!

[daz]

I think you need/want something like : https://www.firstlightoptics.com/adapters/baader-click-lock-2-for-celestron-meade-sct.html

 

[Geoff Lister]

If the camera still has its neck strap attached, loop it over part of the OTA; possibly the base of the finder bracket, or the dovetail clamp knob.

Geoff

[celestron8g8]

If you are using the bracket to attach the DSLR to the Eye Piece then I warn you to stop doing that now !  Those brackets are for small light weight cameras . To properly attach a DSLR to Prime Focus (PF) of your scope there are several ways but not all are good cause of safety for your camera and scope . Watch this video from Celestron . It shows proper use of light weight brackets and how to attach your DSLR  PF to your visual back of your scope :  

 .  A T-Ring is mentioned and a T-Adapter is mentioned . You have the T-Ring , do you have the T-Adapter like in the video you posted or a different type ? I highly recommend the T-Adapter that is mentioned in the video that I posted  :  

https://www.celestron.com/products/t-adapter-for-schmidt-cassegrain-telescopes 

Mount the T-Adapter to the T-Ring as mentioned in the video and then screw it into the back of the Rear Cell on your scope . You will need to remove the Visual Back first . Just tighten snug and whatever you do Please Do Not over tighten ! This is called Prime focus and as mentioned it's a great way to image planets and the moon cause exposures are short but if in the future you learn and do DSO (Deep Space Object) imaging you will need a guider for your scope to guide cause DSOs' need long exposures and without a guider you will have star trailing and a bad looking image . 

[Cornelius Varley]

In the video he attaches the camera body to the visual back (short tube at the rear of the telescope) using a t-ring and t-adapter. The visual back also has a t-thread at the rear end so he could have attached the camera and t-ring directly to the visual back without the need for the adapter. The nosepiece of the t-adapter also had an undercut so unless the screws were not sufficiently tightened it should not come off.

[Galen Gilmore]

What they said ^^^

But I honestly doubt that the camera would fall out, the screws on the focusers are surprisingly sturdy, and don't usually slip or get loose.

Edit: Disregard my comment, I think I was confused on the type of adapter you were using.

[Cornelius Varley]

Or wrap the camera strap around the finderscope bracket.

[celestron8g8]

20 minutes ago, Cornelius Varley said:

In the video he attaches the camera body to the visual back (short tube at the rear of the telescope) using a t-ring and t-adapter. The visual back also has a t-thread at the rear end so he could have attached the camera and t-ring directly to the visual back without the need for the adapter. The nosepiece of the t-adapter also had an undercut so unless the screws were not sufficiently tightened it should not come off.

I'm pretty sure I understand what your saying but let me verify something first . Are the thread measurements on the rear of the rear cell the same measurements as the T-Rings inside thread measurement ? If this is possible what about Vignetting  , wouldn't there be more than with the T-Ring I suggested which is what I have and used ? The visual back is 1.25" where as this T-Adapter helps reduce some vignetting  :  https://www.celestron.com/products/t-adapter-for-schmidt-cassegrain-telescopes

 

I don't believe it will . This is from https://www.highpointscientific.com/celestron-canon-eos-t-ring-for-35mm-slr-cameras-93419

Please Note: This T-Ring has 42mm threads, which fit all APS-sized Canon EOS cameras. If you have a full-frame Canon EOS you will require a 48mm EOS T-Ring. A few o

Please Note: This T-Ring has 42mm threads, which fit all APS-sized Canon EOS cameras. If you have a full-frame Canon EOS you will require a 48mm EOS T-Ring. A few options are shown to the left in our Accessories section.

ptions are shown to the left in our Accessories section. 

[Cornelius Varley]

Both the thread on the rear of the visual back and the t-ring are M42x0.75mm.  The SCT t-adapter will also work.

[celestron8g8]

5 minutes ago, Cornelius Varley said:

Both the thread on the rear of the visual back and the t-ring are M42x0.75mm.  The SCT t-adapter will also work.

Thanks for the Info cause I have all those adapters but never tried the Visual Back to my T-Ring . That's good to know , saves a few bucks for others that haven't already bought all the adapters I have ... 

[Sedna]

1 hour ago, celestron8g8 said:

If you are using the bracket to attach the DSLR to the Eye Piece then I warn you to stop doing that now !  Those brackets are for small light weight cameras . To properly attach a DSLR to Prime Focus (PF) of your scope there are several ways but not all are good cause of safety for your camera and scope . Watch this video from Celestron . It shows proper use of light weight brackets and how to attach your DSLR  PF to your visual back of your scope :  

 

Hi celestron8g8,

We did just what the guy in the video says to do at 5:44. Yes, there was a T-adapter *and* a T-ring, sorry I did not specify earlier. You warn against using the "bracket to attach the DSLR to the Eye Piece " which I don't think we're doing--again, we're using the T-adapter and T-ring, no eye piece (though I believe the barlow lens can be positioned between the camera and the scope?). Which bracket are you referring to? Sorry for the dumb question.

-Sedna

[Sedna]

Also, a follow up question about the optical tube: the instruction manual says that some models come with a safety screw to prevent the tube from sliding along the dovetail bar. Mine did not come with one ... do they sell these separately? Also, when I tighten the screws on the dovetail bar, there are some little dimples in the metal of the bar afterwards. Is this normal (I'm assuming/hoping the metal is supposed to be soft enough to absorb some of the pressure), or am I over tightening?

[celestron8g8]

The bracket I’m talking about is the one attached to the Eye Piece . I never do that . Marks on the dovetail are normal when you tighten the screws , no big worry there but in your box the accessory bags should have both screws to attach the scope to the mount . They both are needed to hold the OTA in place securely . If you didn’t get it call Celestrons support and tell them you just got the scope and the screw your talking about was missing and they will usually just send you a free one in mail . 

[Sedna]

21 minutes ago, celestron8g8 said:

The bracket I’m talking about is the one attached to the Eye Piece . I never do that . Marks on the dovetail are normal when you tighten the screws , no big worry there but in your box the accessory bags should have both screws to attach the scope to the mount . They both are needed to hold the OTA in place securely . If you didn’t get it call Celestrons support and tell them you just got the scope and the screw your talking about was missing and they will usually just send you a free one in mail . 

Thanks, correct, I was never using anything attached to the eye piece.

Ok, so the missing screw: I actually have *both* the screws that screw in to hold the optical tube in place (i.e., the screws which form small dimples in the metal of the dovetail bar). What I *don't* have is a safety stop screw, i.e., a bolt that goes into dovetail bar and would catch on the mount were to the tube to start sliding. This does not appear to be included with all scopes .... does that match your understanding? Can I just put a one-inch bolt in the threaded hole and use this as my safety stop?

[celestron8g8]

57 minutes ago, Sedna said:

Thanks, correct, I was never using anything attached to the eye piece.

Ok, so the missing screw: I actually have *both* the screws that screw in to hold the optical tube in place (i.e., the screws which form small dimples in the metal of the dovetail bar). What I *don't* have is a safety stop screw, i.e., a bolt that goes into dovetail bar and would catch on the mount were to the tube to start sliding. This does not appear to be included with all scopes .... does that match your understanding? Can I just put a one-inch bolt in the threaded hole and use this as my safety stop?

So are you talking about a hole in the dovetail that is attached to the scope that you mount on the head of your scope mount ? If so then really no need of that . The two screws in the head  where the dovetail slides into those screws are sufficient to hold the OTA in place . I've never worried about any other bolts for that . 

 

[Sedna]

15 minutes ago, celestron8g8 said:

So are you talking about a hole in the dovetail that is attached to the scope that you mount on the head of your scope mount ? If so then really no need of that . The two screws in the head  where the dovetail slides into those screws are sufficient to hold the OTA in place . I've never worried about any other bolts for that . 

 

Right, I have these two screws in the picture. Guess the other bolt (safety stop) is optional.

[JamesF]

I thought the Celestron visual back had some thread other than T2 on the back for some reason.  I can't check what mine is at the moment -- I've had a focuser on the back of my C9.25 for longer than I can remember.

My 127 Mak definitely does have a T2 thread on the visual back though, so perhaps the Celestron models also do.

I'm rambling.  And I'm not even dressed for it.  Exceptionally unpleasant visit to the dentist this morning and I'm still a bit out there.  I'll try harder next time.

James