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NexStar 130 SLT - help and advice


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Hi,

I just received this telescope as a gift form friends for my 30th birthday.
I'm into photography ... mainly macro shots of insects (a stark contrast from the massive night sky ;)).  See my gallery here.

Anyway I have a bunch of questions so if anyone can help me out with some answers I would really appreciate it.

1. Any idea how long the batteries will last?  They haven't gone flat on me yet, but I haven't spent more than an hour with the scope yet.
2. Should I buy this
3. If I do buy that what cable would I need to hook it up
4. Can anybody recommend me a cheap eyepiece with a cross-hair for use in alignment
5. Can anybody recommend me a barlow lens?
6. Can anybody recommend me a T mount adapter for canon for planetary imaging?
7. I have found out that for DSO photography I would really need have equatorial alignment.  The option is available on my GoTo handset .... can the NexStar 130 SLT do this?  I'm guessing that it cannot.  If not .... is it possible to adapt it somehow so that it does or do I really need a different telescope for this?
 

Massive thanks in advance
- Craig

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1. No idea, but I would not trust them as low power has bad side affects. I keep the battery bay loaded but only as a backup.

2. Should I buy this ? I have something similar which works for me.
3. If I do buy that what cable would I need to hook it up: One of these http://www.firstlightoptics.com/astronomy-cables-leads-accessories/skytron-power-supply-cable-for-skywatcher-celestron-mounts.html

4. I have no problem with the RDF.
 

5,6&7 I leave to others to respond.

For advice on alignment note that the software is the same/similar between the Nexstar 127SLT, 130SLT and SE series so I suggest searching the forum. fwiw I use two-star align.

HTH

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Craig, welcome to SGL

1) I wouldn't rely on AA's... you might get an hour or two of use, but beyond that, the tracking will degrade. 

2) I used one of those (or one like it anyway) with an SLT and it worked great... many hours use on a charge

3) FLO (link at the top of the page) will be able to sell you a suitable power lead... http://www.firstlightoptics.com/astronomy-cables-leads-accessories/skytron-power-supply-cable-for-skywatcher-celestron-mounts.html

4) you shouldn't need a cross hair ep. Aligning on a star, slightly defocused, in your highest power (shortest focal length) ep should be more than sufficient, it was for me

5) If you can get one, the Tal x2 is a good one for the price. Otherwise, the price goes up a lot.

6) For planetary, a dSLR is completely the wrong tool. A webcam is a much better bet for a couple of reasons. As the target you are looking at imaging is such a small target, you're wanting to get an equivalent focal length of tens of meters, and doing that with an SLR is... nigh on impossible. Using a webcam with an 8.5x crop factor makes this much easier. Also, the frame rate on an SLR is too low, wheras with a webcam type camera you can often shoot at much higher frame rates (this helps with the atmospherics).

7) For DSO, an EQ mount is preferable, and whilst the controller does support an EQ mode, the SLT does not have the facilities to do so. The handset, is I believe, the same handset as that used on the larger Nexstar mounts which do support a wedge to allow for EQ mode. I'm not sure if you can easily reach focus with the 130 and a dSLR, I've not tried it, but have read it's tricky. However, if you were to purchase a medium length dovetail (http://www.firstlightoptics.com/dovetail-bars/skywatcher-dovetail-mounting-plates.html) you can mount your camera directly to the dovetail, and image with that. You will be limited to a maximum of 2 minute exposures low in the east and west (if the drive accuracy can cope), and as you get higher and further North/South, the exposure time will come down. To around 25 to 30 seconds. The focal length does not affect the exposure times directly, but it will cause different strains on the mount. 

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Thanks for the replies guys.  Very helpful. 

About 6 and 7 .....

6.  I am confused as to how a webcam would be better than a dslr.  I understand what you are saying about crop factor .... but surely I could shoot an image on an SLR and then crop afterwards and result in an image with less noise then a webcam (full frame dslr).  When you mention framerate are you talking about filming a planet rather than taking individual images and then combining the frames to make a final image?  Could this not be done with higher res photographs?

7. So could I buy an EQ mount and then put my 130 on that?
Could you further explain the dovetail thing.  Im not really sure what you are suggesting in terms of mounting the camera/telescope to what?

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6 some of the cameras available allow a frame rate of 60 fps, you'd then shoot 1000 frames and stack them, combining the best 30% (or so) this deals with the noise and the stacking software uses the frames that have the least effects of the atmospheric diatirbances.

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7 you could get an eq mount and put the 130 on top. Before investing any money on kit, get 'Making Every Photon Count', it's in the books section on FLO. I'm on my mobile at the Monet so can't get at the pages now.

A dovetail bar is used to connect the scope, or other things to the mount. The 130 will have a short piece that connects to the mount, but you won't be able to balance the system easily as it's too short for that, just enough to balance withte supplied ep's. you can get a dovetail and put something like a Manfrotto 323 adapter on the dovetail bar and mount your camera and lens that. Or even mount a ball head on tote dovetail.

If you want, I can dig up some of my dso images with my SLT mount

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Thankyou.  Yep I'll go buy that book.
Id love to see you images if its not too much inconvenience!

I get the webcam thing ... really short exposures so you quickly rack up a 1000 and then lob them in the software.

But if I shot 1000 images on a FF DSLR ... the quality will be better ....?

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oooo one other thing.  I totally get the need for a solid mount to get the best images like an EQ6 (eyeballed that earlier) but is there a poor mans way to get into DSO .... some way of modding what I have maybe?

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I'll dig them out later. You should be able to do some nice widefields with just you am era and lens mounted on a dovetail. Probably cost under £50 ish for the cable, power supply, and dovetail. I assume by the mention of ff dslr that you have some nice lenses and a suitable ball head.

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Ok, here's a few, they were all shot with an ST80, so short and lightweight, and prone to CA, thus the blue halos (and I was using a Semi APO filter to reduce the CA a bit, and lost a lot of blue), with an unmodded 450d. And I'm a lot better (I think) at processing nowdays too.

m42repro2.jpg

m38adj3.jpg

m52bubble.jpg

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Thanks Craig. These were all shot with my ST80 clone (400mm) @ f/5. So if you have something like the 100-400 or a 400mm prime, you can achieve that same FOV... Have a look at http://www.12dstring.me.uk/fov.htm for an idea of the FOV you can achieve with various focal lengths. 

It looks like you have an MPE65 at least... cracking set of Macro shots on your stream Craig. If you wanted to post them on here, you might want to give a warning in the title that there are some extreme bug and spider macro images in the thread though ;).

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Thanks!  Ha ... well this is the thing.  I don't have an MPE65 .. I don't have a macro lens either.  :)  I love figuring out how to do things for cheap.  My macro rig (not including the body) cost around £60 to build.  It's really a case of technique with macro rather than gear.  I've started reading how equatorial mounts are built .... looks complicated.  Its still going to be a long while before I get one I reckon .... I've only just managed to figure out how to align my scope at all.

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You're getting great results with it, whatever it is. I've only recently gotten myself a macro lens, yet without it have managed to get up to  11x magnification.

EQ mounts can be a lot more complex to understand and get to grips with than a simple AltAz, but they are better suited to AP. 

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  • 7 months later...

Thanks!  Ha ... well this is the thing.  I don't have an MPE65 .. I don't have a macro lens either.   :)  I love figuring out how to do things for cheap.  My macro rig (not including the body) cost around £60 to build.  It's really a case of technique with macro rather than gear.  I've started reading how equatorial mounts are built .... looks complicated.  Its still going to be a long while before I get one I reckon .... I've only just managed to figure out how to align my scope at all.

Cheap lol thats my fave word. 

i run an ST80 coupled to a Canon 350D direct Tmount to canon eos adapter 

i also grabbed a revelation t mount afocal adapter ( like an externder tube but an eyepiece fits inside it)

check out the FOV website, pop in 450D and choose your scope from dropdown.

choose mars as object and click submit. its going to be a small dot if you can see it.

Now keep the same scope but add this webcam " microsoft lifecam " and click submit 

big difference, the smaller chip can have a smaller light cone cover it all.

on our DSLR that light cone is very small so we get a small image on a huge sensor.

now select M42 and swap to the canon 450D , nice image right ? 

now change to the microsoft webcam , ergh its to big and raspy , thats a small sensor in a huge light cone

DSLR is mainly used for those sweet full lunar discs , those white light sun images and DSO

Webcams are planet slayers, the small sensor size outweights the DSLR large quality sensor.

Most imagers will have a selection of cameras, webcam dlsr and even a dedicated astronomy camera.

a different tool for a each certain job 

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