Synq

https://www.firstlightoptics.com/other-collimation-tools/rigel-aline-collimation-cap.html
I need a cheap collimating cap with quick delivery and I am wondering if this will help me do the job.

Thanks.

31 minutes ago, Girders said:

Hi Synq,

Firstly, I'm not into the astrophotography side of things, but I do have this camera.  This is a bridge camera with a built-in long zoom (12x?), so there's no way to attach it directly to a scope like you would a DSLR.  It's also probably too heavy/awkward to attach using a phone adapter behind an eyepiece.  I think I tried at one point setting it up on a tripod behind a scope but was never able to align things correctly.  If I remember correctly you'll also have the problem that the maximum exposure length is short to keep the sensor from overheating - 4 seconds maybe?  As such you'll probably find you can get better results using your mobile phone for bright planets or the moon - and even for the stars if your phone has a good night sky mode.  Sorry that's not more helpful.

On the plus side, I found this a brilliant camera for taking shots of the northern lights on a trip to Norway - much better than he Fuji HS-20 that we'd bought several years later.

If anyone else has had more success using this camera I'd be delighted to hear about it!

Thanks so much

I just need someone to give me an idea if this is fine to start with. Thanks.

As I open the box, the sky is covered in clouds

2 hours ago, Pixies said:

The only way you can adjust it is along the axis of the arm holding it. I would expect that it will be central perpendicular to that - unless the arm has been bent. 

I mean - make sure this bit: 

is not twisted - ie. the top face of it is parallel with the plane of the end of the tube. It does sound like you have had issues with this. How is it fixed to the arm normally? Is it screwed in?

Assuming the above is OK, a good way of doing this is to wind out the 3 adjusters and tighten the central screw, which will gradually bring the mirror back up the tube. Keep going until you have brought it all the way up and it is flush with the bit arrowed above. Then, bring it back down the tube by slackening the central screw and taking up the slack by tightening the 3 adjusters by equal amounts each time. The mirror will move back down the tube but remain parallel with the top bit. Keep going until it is centered under the focuser.

yes - loosen the 3 adjusters, or slacken the central screw slightly. This open design makes it easy to see the orientation of the mirror. You are trying to rotate it so that it is 'facing' the focuser. The elliptical shape should be aligned so that the 'long' direction is in line with the focuser. It is shaped so that it appears as a circle in the focuser, when it is facing it like that.

 

This all appears very complicated at first, but once you get your head around what you are trying to achieve, it should make sense.  The fact that your secondary assembly could rotate on the arm is a problem that needs sorted though. Perhaps another heritage owner can comment?

I’ll try to follow the guide and your steps.

Thanks so much.

5 hours ago, runway77 said:

if you have a f/5 or faster telescope you might not necessarily be able to see the clips. this is the case for my 150 pds. In my f/6 dob I can see all three clips in the cheshire eyepiece. 

I have an f/5 scope.

53 minutes ago, Tiny Clanger said:

Are you sure you solved your previous problem ?

https://stargazerslounge.com/topic/366620-secondary-mirror-keeps-tilting-and-not-staying-in-position-after-first-attempt-in-collimation/

Thanks for the concern. I lodged a bit of folded paper between the rod and mirror as a temporary fix. It doesn’t move and will only move if I push or pull it.

I just don’t know which way I point it. Do I point it where the primary mirror is centred within it?

41 minutes ago, Pixies said:

Hi,

You might want to have a smaller eye-hole. On a Cheshire or collimation cap, the hole is usually around 2mm in diameter. You really need to make sure your view is dead-centre of the focuser.

Can I suggest you google "Astro Baby Collimation Guide", it'll really help. But I can see a few things that should help too.

Before you start, you really need to make sure that the secondary assembly is central in the tube. Measure the distance from the middle of the centre screw to the outside of the tube in several directions, it should be the same distance in all directions. Also - which only applies to these types of secondary assemblies that have a single arm attaching them to the tube - make sure the outer surface is completely parallel with the outside edge of the tube end. I hope you understand what I mean - that it hasn't twisted around the rod.

I can see that the secondary mirror holder is tilted away from the other part (with the screws). Here: 

and here:

This has happened because you have tried to align with the primary, when the secondary was twisted.

I would suggest that you try and get these 2 parts parallel right at the start. The 3 secondary adjuster bolts should all be at the same depth to start with, before you try to rotate the secondary to get it looking circular in the collimation cap view.

 

Does that make sense? Drop me a PM if you want a hand

 

 

So first of all, let’s say I measure from the secondary mirror centre screw to the outer edges in different places and the distances are not the same, how exactly do I centralise it?
 

“Make sure the outer surface is completely parallel with the outside edge of the tube end.” Would you mind explaining this further? I don’t understand.

I will adjust the 3 bolts so they are the same length.

Lastly, how do I rotate the secondary mirror to get it circular? Do I loosen the 3 adjustment bolts and rotate the mirror manually?

Thanks.

59 minutes ago, Pixies said:

I think your secondary is rotated. It looks like the top of the secondary (in the picture) is rotated away from the focuser. You can see this in the reflection, too.

Can you post a picture of the above view, rather than a video. Also, how big is the hole in the collimation cap?

Half a centimetre

I try to collimate telescope because Jupiter and Saturn looked bad and I center primary in secondary and I make secondary look as circular and centered in focuser as I could with my equipment (home-made collimation cap). Then I align secondary in primary with the back nobs at the far end of the telescope. When I look in focuser I can only see one of the primary mirror clips fully, then other one by a half and last one, I can't see. I tried rotating secondary mirror rotators to no avail. Help.

Looking for a under £30 Barlow Lens for my Heritage 130P scope. Recommend some please. Thanks.

On 26/11/2020 at 16:06, johninderby said:

 

Both the cheap one I linked to and the Celestron are mostly plastic. The cheap one is fairly solid and bending isn’t a problem.

Thanks I’ll look into the cheaper one as a temporary till I can find a good webcam for my dobsonian

3 hours ago, johninderby said:

Thos is the best cheap smartphone holder I’ve found. Grips the eyepiece well. The Celestron is better but a lot more expensive.

https://www.amazon.co.uk/Prismáticos-Monoculares-Telescopios-Astronómicos-Microscopios/dp/B07QLB16Y9/ref=sr_1_8?dchild=1&keywords=smartphone+telescope+holder&qid=1606395152&refinements=p_76%3A419158031&rnid=419157031&rps=1&sr=8-8

Is it plastic and would be bend under the weight of a phone?

Last adapter I brought was a plastic piece of junk. Please recommend me a good one please.

Prefer one that could actually hold up the weight of my phone.

1 hour ago, DaveL59 said:

A good guide oft quoted here is astro baby's one

Astro Babys Guide to Collimation - Newtonian Telescope - Reflector (astro-baby.com)

What tools do you have, collimation cap/cheshire etc?

Handmade collimation cap as seen in the video

6 minutes ago, DaveL59 said:

Seems that the single stalk holding it is loose at one end, hence it flops when you let go. Does it clamp on a screw holding the focuser on the carrier? There may be a lock nut on the end of the shaft too that needs tightening up so it hold firm.

Yeah there is a nut at the end, I'll try tightening it. Thanks. And by the way do you know any good collimation videos, I seem to have made it worse.

Hi I am fairly new with telescopes and I noticed my telescope needed collimation. I preview the collimation at the beginning (tell me please if its alright) however after I finished the secondary mirror kept tilting and not staying in place as seen in the video. This is a Heritage 130P telescope. Please help.