T Adapter for Skywatch 130mm

[jason32]

Hi guyz,

I want to attach my canon 600D to my telescope skywatcher explorer 130mm. I found this adapter on ebay which also comes with t mount and a barlow built-in:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160786033057&ssPageName=ADME:X:RTQ:GB:1123

Is that any good? The seller told me it will fit skywatcher too. But do I really need to use barlow for focusing?

[Stephen]

You won't be able to focus your DSLR on the 130P as standard I'm afraid, you can't get the camera close enough to the secondary.

Whilst a Barlow will allow you to focus, it's going to slow your scope (your exposures will need to be 4 times as long) down terribly.

[jason32]

Then what should I do?

[Stephen]

With that scope your best bet is to probably stick with lunar / planetary imaging with a webcam rather than your DSLR

[Fandango]

Oh Poo!

I bought my scope specifically specifically because I wanted to take photo's of deep space: I was just about to buy a DSLR camera! Not knowing anything about astronomy when I made the purchase I just did the best I could and went for a scope recommended by the Sky at Night. I am hacked off. I have enjoyed looking through my scope but what a waste of money (In a deep space photography sense).

Is this an issue with all newtonian reflectors? They didn't mention that on blumming StarGazers live! That program was incredibly misleading.

[jason32]

Oh Poo!

I bought my scope specifically specifically because I wanted to take photo's of deep space: I was just about to buy a DSLR camera! Not knowing anything about astronomy when I made the purchase I just did the best I could and went for a scope recommended by the Sky at Night. I am hacked off. I have enjoyed looking through my scope but what a waste of money (In a deep space photography sense).

Is this an issue with all newtonian reflectors? They didn't mention that on blumming StarGazers live! That program was incredibly misleading.

Yes man I bought mine specifically for dSLR photography and the salesman told me its a great scope for that purpose. blumming LIARs...

[Stephen]

Oh Poo!

Is this an issue with all newtonian reflectors? They didn't mention that on blumming StarGazers live! That program was incredibly misleading.

Skywatcher seem to of got on the ball with people wanting to slap DSLRs onto the reflectors, in recent years they have redesigned the focuser on the larger (150,200,250) scopes to allow a camera to get closer and achieve focus.

Older scopes need to have their focusers replaced or primaries moved or DIY solutions to get focus though.

Yes man I bought mine specifically for dSLR photography and the salesman told me its a great scope for that purpose. blumming LIARs...

That might be something to take up with the salesman, but I'm not convinced anyone would recommend that scope as being great for DSO. Some people have hacked theirs about .... but it's not something I could really advise nor would want to recommend!

Might I refer you both to this excellent book:

http://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html

If you really have an ambition to get into DSO photography, you could do a lot worse than read that through and really get an understanding of the kit, time and cost requirements to get started

[steelfixer]

Jason32

There might be a way around this I think.

You can move the primary mirror up the tube thus moving the focal point out further at the EP.

That is assuming your 130 does not have the focal lens in the base of the focus tube.

If it does then I think you are stuffed.

If it does not have the lens then stick a thread on the DIY section about moving the mirror.

There are a lot of very clever people on there who will tell you exactly what you need to do to achieve this.

[brucen]

That's strange because the Skwatcher website description of the 130P says "Short focal length design, ideal for astrophotography". I haven't used mine for deep space but have used a SLR for lunar shots and had no problems. I think they may have changed the design a couple of years ago and perhaps the focus issue was sorted out?

[Stephen]

That's strange because the Skwatcher website description of the 130P says "Short focal length design, ideal for astrophotography". I haven't used mine for deep space but have used a SLR for lunar shots and had no problems. I think they may have changed the design a couple of years ago and perhaps the focus issue was sorted out?

I suspect you will find the difference in focus position for a DSLR between the relatively close moon (or maybe planets, but a webcam is more suited) is very different to the distant DSOs.

I stand to be corrected, but a quick search for "130P" and "DSLR" will reveal dozens of threads covering this issue on the forums

[Monki]

I don't think stargazing live was deceptive...I think people expected too much from the night sky and telescopes after watching a television program. People spend thousands to get nice DSO pics. It requires research, time and patience.

What is misleading is skywatcher mentioning it as a good scope for photography.....unless it has been changed.

@Stephen. I always assumed once the focus was at infinity ie the moon, planets and dso that no refocus was needed when changing between objects? It seems true with planets and the moon..I just expected DSOs would be the same :S

Not sent from a Galaxy S2 on Slim ICS.

[David JM]

With all the back focus issues with 'scopes I would have thought by now that the makers would have done something to sort it out, any reason why Newts are still struggling to be equipped with DSLRs? Laziness on behalf of the manufacturers?

[Stephen]

With all the back focus issues with 'scopes I would have thought by now that the makers would have done something to sort it out, any reason why Newts are still struggling to be equipped with DSLRs? Laziness on behalf of the manufacturers?

Because if you make the focuser low profile by default to accomodate the DSLR, you have to use an extension tube for your EPs maybe?

The issue is with the secondary / CCD distance, webcams "typically" don't have this problem nor do EPs.

However as I pointed out several posts up, the manufacturers are changing the designs to accomodate DSLRs A new 150P/200P out of the box will focus with a DSLR onboard.

[acharris77]

Hey, I think the confusion of the focuser and the focus issue is coming from the 2 differrent 130p out there. The 130p or 130m which comes with the EQ2 mount or I think the supra trak, only has the standard 1.25 focuser, and this is why the autofocuser by skywatcher wont fit without modding the bracket that comes with it.

But the 130p which comes with the AZ Syncan Goto is fitted with a Rack and Pinion 1.25" / 2" focuser which allows the skywatcher autofocuser to be fitted direct out of the box with no modification and also it has the part that screws off on the focuser tube so you can directly attach an adaptor for a DSLR which is what I think would allow the 130p to maybe achieve focus as it is better positioned.

I found it strange how only 1 of the 130's out there was fitted with a dual 1.25 /2" focuser and every other 130 is fitted with the basic 1.25 focuser. As with a modified webcam I can achieve focus with a bahitov mask and take images of DSO's even with the AZ mount and do stacking of various 15 second exposures without trails.

[dav1d]

Not forgetting the 130p flextube, which allows you to physically shorten the tube to achieve focus

No good for long exposures on a dob mount though - can't have everything

[jason32]

Someone mentioned that if I use a X2 barlow with my 130m then I'll be able to focus using my dSLR without modifying the scope in any way? Has anyone tried that?

[Fandango]

How do I know if I have the Rack and Pinion 1.25" / 2" focuser. I did try to search on the internet for the different types on the 130p without success.

I did find a review of the SW130p Syscan AZ written in 2008 for Stargazers Lounge and due to the description of parts of the scope and the stand I am wondering if I got posted an older telescope. It certainly didn't match the reviewers scope.

[David JM]

Because if you make the focuser low profile by default to accomodate the DSLR, you have to use an extension tube for your EPs maybe?

The issue is with the secondary / CCD distance, webcams "typically" don't have this problem nor do EPs.

However as I pointed out several posts up, the manufacturers are changing the designs to accomodate DSLRs A new 150P/200P out of the box will focus with a DSLR onboard.

I don't know ['cos I don't have one] if a focuser could be made that would have enough 'reach' to do both, but I bet one could. I'm surprised that after what must be nearly 20 years of DSLRs being around that some scopes still can't be used with a camera.

[acharris77]

Sorry the reply is late, but to check if you have the 1.25" / 2" Rack and Pinion check it against the picture of this one which is on my scope:

[x6gas]

To all intents and purposes as far as focus is concerned the moon and all of the planets and stars are all at infinity. Before I invested in a Bhatinov mask I used to focus my DSLR on the moon (if it was available) before doing DSO imaging.

My Celestron 6" newt also has a focuser where you can unscrew the end of the drawtube and directly attach a DSLR t-adapter. So as said above it is possible to design things in such a way that you can use a newt for DSO photography and reach focus with EPs without the need for extention tubes. This is ridiculously poorly documented though and my first 100 posts on here seemed to be explaining to other C6N and Skywatcher 150 owners how to attach a DSLR in order to achieve focus... which I was very, very happy to do by the way!

[Welrod50]

All,

May I throw my two penneth in...

I have the SW Explorer 130 (900mm f6.92) and it is the newer black bodied version. I have found that, as with camera lenses, the 'f' number is crucial as a lower number will allow more light in at the expense of absolute image sharpness. That is why refractors are like f10 onwards, as they let less light in accordingly, but image sharpness increases. Therefore, f6.92 occupies the mid ground, so really, it should (and in my view, is) ok for astro photography - from my complete amateur at astro imaging, point of view!

Now, for some reason the focuser is threaded for T adapter use. I assume that the company mass produce the focuser for use on other scopes, hence the adapter, as it is pointless on the 130 as the tube will not allow prime focus. Now, you can either use a Barlow, but I purchased a SW 8-24mm zoom EP which, if you remove the rubber eyecup, is threaded for T adapter. I have attached my Pentax Kx to the EP and it works a treat. Using the zoom on the EP to act like a zoom camera lens without any drop in exposure.

However, from experience, I have found that the exposures needed at night mean that even with mirror lock - the tiny vibrations from the camera shutter closing at the end of the exposure introduces image blur.

If however, you have a DSLR with video function, you can use this in the same way as a webcam - take video instead and then edit it and stack it in registrax to complie a clean, image noise free picture.

I use VirtualDub to load the video, crop the beginning and end out (to effectively use the part of the footage with no wobble at the start and end) and then stack the frames from the remaining footage with Registrax. It works well, although I have only had chance to try this twice so far due to cloud/weather/work etc.

Hope that helps