New Astrophotographer in need of advice

[mhomami]

Hello all,

I've just joined this forum to take advantage of the wealth of knowledge I'm seeing floating around. I'm very new to astrophotography so please be gentle with me.

A quick overview of my kit:

Celestron Astromaster 130EQ

3x Barlow (Telescope 3x Barlow For Increasing your magnification: Amazon.co.uk: Electronics)

T-mount (http://www.amazon.co.uk/gp/product/B001F7UA5M)

Sony Alpha a230

I bought this stuff a year ago while I was living in Glasgow and never touched it as I did not have the time. I now live in Farnham and the dark sky's here are too perfect to waste. So last night I dust off the old telescope, fiddle with the poorly constructed mechanisms and after about half an hour I get my first glimpse of Jupiter. That tiny blob of distorted light was, to me, more breathtaking than all the crisp and clear pictures I've ever seen of Jupiter.

So I tried to take a picture with the t-adaptor and the barlow I had bought for just this purpose. For some reason I couldn't get it to focus at all. It seemed that the barlow wasn't directing the light correctly.

I tried the barlow by itself with my 10mm popped through it and all is fine. A little blurry due to the magnification but clear enough to just barely make out the different bands on Jupiter. So I took out the 10mm, mounted the a230...and I get the big blob again.

Am I correct in concluding that the planet is out of focus because the extension provided by the barlow is insufficient?

Perhaps I am not fitting the barlow and t-adaptor correctly or did I buy the wrong kind of barlow? This one doesnt let you unscrew the lens at the bottom. I did try popping out the lens at the bottom of it by pushing it through the plastic casing of the barlow but that didn't work either.

On a side note, I successfully shot the moon with the barlow and t-adaptor focusing through the cameras viewfinder. Again the focus was off in comparison to what I could see with the barlow/10mm combo but there was no mistaking that the pictures were of the moon.

Any help would be much appreciated as I have spent hours on this and simply cannot figure it out.

[jgs001]

Hi welcome to SGL.

It sounds like the Jupiter image is probably over exposed, so you won't be able to tell if it's in focus or not. I'd guess you used the exposure meter in the camera ?? If so, then the camera has been fooled by the large amount of black around the bright planet. You have to go manual and experiment... you could try something like 1/100s at ISO100 and see how you go... Ignore the exposure meter.

Focusing is going to be really hard, even if you can zoom in all the way on a liveview display... using the viewfinder is just going to make that tougher.

Go for the moon to start with, and get the focus as good as you can. Then swing around to Jupiter. Don't adjust the focus. Shoot an image, and zoom in to check the planet... if it's a blob, increase the shutter speed a bit. If you can't see it, decrease it a bit... trial and error is, I'm afraid, the only way to find the right exposure setting. Even then, Jupiter is going to be very small in the SLR frame, but good luck.

[barkis]

I would suggest using a x3 Barlow is pushing the limit.

The focal length is almost 2000mm, and will make focusing very exacting.. Your objective size limits the amount of detail it can resolve, so high magnification is pointless.

Johns given good advice on exposure, aand should be followed too.

Don't be too ambitious to start with, build your way up gradually.

Good Luck.

Ron.

[mhomami]

Thank you for both your responses.

John, I shall check the exposure settings on the camera tonight and hopefully I'll get a chance at shooting the moon again.

Ron, from the reading I have done it would appear that the magnification offered by the barlow distorts the picture quality as you have already said. I was thinking about purchasing this 2x barlow to help with this. I cannot find anything with a lower magnification:

31,7mm (1.25") Achromatic Super Barlow Lens Eyepiece 2x | eBay

My telescope has a focal ratio of f/5. I understand that this is quite fast for these telescopes but would appreciate your advice on whether the above short barlow is appropriate or if I need a longer barlow like this one:

1.25" 2x Achromatic Barlow Lens | eBay

Thanks again.

[jgs001]

I don't believe the length of the barlow is going to make any difference. a 2x is a 2x sort of.

First Light Optics - Skywatcher Deluxe 2x Barlow

might be better... importing from the US could cost a lot more in import duties, VAT and shipping.

Anytime you add more glass to the mix, you can degrade the image. Also, the higher the magnification used, the more you will be affected by things like atmospheric turbulence etc.

To be honest, an SLR is not really the right tool for the job, it can produce results, but it's much harder than something like a webcam for the planets.

[mhomami]

Perfect. Thank you very much. I'm looking forward to trying this out.

I will have to upgrade to an spc 880 at some point but for now I will be in enough trouble with the missus

I've also read that dslr's are better for deep space photography and this is my ultimate goal. I do not have a clue how i'll be able to find anything in the sky but I will try!

[jgs001]

to be honest.. for Deep Sky, your next purchase should be

First Light Optics - Making Every Photon Count - Steve Richards

or I'm sure it would make a good xmas pressie with enough hints

[mhomami]

Sounds good John. I'm sure it will be a valuable addition to the hobby set