To Barlow or not to Barlow that is the question?

[budgierless]

Hi guys,

I have a skywatcher exploer 130p telescpe and nikon d5200 DSLR.

I been reading alot about astro imaging and i know that a t-ring and barlow is needed, but i would like to know if i can use THIS instead as it seems impressive for the job? if not why? would this effect my image?

please advise.

thanks

Phillip

[glowingturnip]

you need a t-ring for your camera, (like this http://www.ebay.co.uk/itm/Adapter-Ring-For-T2-T-Mount-Lens-to-Nikon-Camera-D5200-D3200-D800-D600-D90-DC309-/251513978209?pt=UK_Photography_CameraLenses_Lens_caps_hoods_adaptors_ET&hash=item3a8f66bd61) and a t-adaptor (like this http://www.ebay.co.uk/itm/T-adaptor-T-mount-for-DSLR-camera-T-rings-1-25-diameter-for-telescopes-/121276129039?pt=UK_Photography_Telescopes&hash=item1c3c9edf0f)

the t-adaptors come in two kinds to fit 1.25" or 2" focussers, I think your scope is a 1.25" focuser ?

That would then image at the prime focal length of your scope.  You can put a regular barlow between the t-adaptor and the focusser tube for greater magnification, though that's generally frowned on (though I do it) since it cuts down the speed of the scope for light gathering, and makes guiding more difficult.

Not familiar with the product you mention, others might have used it, but to be honest, looks like a bit of a bodge to me.

[budgierless]

you need a t-ring for your camera, (like this http://www.ebay.co.uk/itm/Adapter-Ring-For-T2-T-Mount-Lens-to-Nikon-Camera-D5200-D3200-D800-D600-D90-DC309-/251513978209?pt=UK_Photography_CameraLenses_Lens_caps_hoods_adaptors_ET&hash=item3a8f66bd61) and a t-adaptor (like this http://www.ebay.co.uk/itm/T-adaptor-T-mount-for-DSLR-camera-T-rings-1-25-diameter-for-telescopes-/121276129039?pt=UK_Photography_Telescopes&hash=item1c3c9edf0f)

the t-adaptors come in two kinds to fit 1.25" or 2" focussers, I think your scope is a 1.25" focuser ?

That would then image at the prime focal length of your scope.  You can put a regular barlow between the t-adaptor and the focusser tube for greater magnification, though that's generally frowned on (though I do it) since it cuts down the speed of the scope for light gathering, and makes guiding more difficult.

Not familiar with the product you mention, others might have used it, but to be honest, looks like a bit of a bodge to me.

Thanks for your reply, yes 1.25" is indeed what is used, why would you say the item i posted looks bodge, dose it not do the same as you suggest?

[glowingturnip]

if i understand the item description, it seems you insert your own eyepiece into that tube, then attach your camera to the top, so the camera's looking through the eyepiece (so-called 'afocal').  You don't need to do that, attaching the camera direct to the scope with the t-ring and adaptor, so there's effectively nothing in the light path between your scope and your camera's chip works perfectly.

[budgierless]

if i understand the item description, it seems you insert your own eyepiece into that tube, then attach your camera to the top, so the camera's looking through the eyepiece (so-called 'afocal').  You don't need to do that, attaching the camera direct to the scope with the t-ring and adaptor, so there's effectively nothing in the light path between your scope and your camera's chip works perfectly.

Just what i wanted to know thanks, im still learning, so its improtant for me to know why not when i ask these questions.

Can you tell me why (aFocal) is bad? sorry if it is a silly question.

thanks

Phillip

[Leveye]

Powermate don't barlow. Trust me there. At least a 2x. Look up! -Lev-

[budgierless]

Powermate don't barlow. Trust me there. At least a 2x. Look up! -Lev-

Sorry i didnt understand your post, im still learning the short-hand terms.

your saying dont get a barlow right? what is 2x for, if its not for a barlow? confusaed now.

[houston]

Hi.. I have used this kind of adapter before digital cameras came about. The grub screw on the side is to secure the eyepiece. A standard 10mm plossl fits in. It worked well with planets with a short exposure.

[budgierless]

Hi.. I have used this kind of adapter before digital cameras came about. The grub screw on the side is to secure the eyepiece. A standard 10mm plossl fits in. It worked well with planets with a short exposure.

Well I have an AZ mount so short-exposures are all i can do, did you have any issues with focus or luck of light etc?

from what i can tell, its seems adjust well for better focus, maybe im wrong, but what cons can you think of from using this?

[lensman57]

Well I have an AZ mount so short-exposures are all i can do, did you have any issues with focus or luck of light etc?

from what i can tell, its seems adjust well for better focus, maybe im wrong, but what cons can you think of from using this?

The contraption you have shown is an adapter to operate the camera - telescope combination in eyepiece projection mode where an eyepiece is inserted into the tube and the camera will then capture the image projected by the eyepiece on the camera sensor. It will work but it has many limitations, the low quality of the capture in comparison to prime focus imaging is one of them. Your 130P however may not achieve focus  with a DSLR in prime focus due to the sensor being so far back from the face of the DSLR ( back focus distance ) so you may have to employ the services of a decent barlow lens  to compensate this . On bright objects such as the Moon or Jupiter this will not be a problem but you may find it difficult to image other dimmer objects. A PowerMate is a 4 element Barlow from the US firm TeleVue, these are highly desirable but very expensive lenses and I don't think that at the moment you should concern yourself with these.

Regards,

A.G

[budgierless]

The contraption you have shown is an adapter to operate the camera - telescope combination in eyepiece projection mode where an eyepiece is inserted into the tube and the camera will then capture the image projected by the eyepiece on the camera sensor. It will work but it has many limitations, the low quality of the capture in comparison to prime focus imaging is one of them. Your 130P however may not achieve focus  with a DSLR in prime focus due to the sensor being so far back from the face of the DSLR ( back focus distance ) so you may have to employ the services of a decent barlow lens  to compensate this . On bright objects such as the Moon or Jupiter this will not be a problem but you may find it difficult to image other dimmer objects. A PowerMate is a 4 element Barlow from the US firm TeleVue, these are highly desirable but very expensive lenses and I don't think that at the moment you should concern yourself with these.

Regards,

A.G

Wow thanks for that,

So would you say i should put my DSLR aside and use a webcam instead then?

[lensman57]

Wow thanks for that,

So would you say i should put my DSLR aside and use a webcam instead then?

Your DSLR will be of use somewhere along the line, but if you  can get hold of a cheap webcam and mod it, it will give you a lot of quality time imaging.I still get a thrill looking at the Moon, our nearest and most neglected DSO  neighbour. With AltAz mount you are also limited to short bursts of imaging ( 20~30s) you can do this manually by keeping the Moon for example in the cross hair of the finder scope, or just take single shots of the Moon using a barlow lens with your DSLR in Prime Focus.  Last year I bought a couple of Xbox webcams from flee bay for about £4.00 and modded one of them. It is no DMK or ASI but it does work and it is cheap and easy to mod.  If you decide to go for a barlow, avoid the two element designs a decent 3 element  2X one costs about £30.00. I have a Revelation 2.5X which I found to be a very decent performer, not a patch on my PowerMate but not bad for the price. Hope you find this helpful.

A.G

[houston]

Im not sure about focus with your scope. I used this with a canon eos 500 and orion optics 6" reflector. Could only manage about 1 second exposure but ok for the moon and jupiter, saturn, venus. Bit expensive tho for something to hold your camera to the eyepiece.

[Owmuchonomy]

Hi guys,

I have a skywatcher exploer 130p telescpe and nikon d5200 DSLR.

I been reading alot about astro imaging and i know that a t-ring and barlow is needed, but i would like to know if i can use THIS instead as it seems impressive for the job? if not why? would this effect my image?

please advise.

thanks

Phillip

I use a similar gadget made by revelation astro at half the price. It's excellent for planetary imaging using EP projection. It combines increasing image scale with an extension tube and can be used with and without the EP in situ. Best accessory I ever purchased.

Here is my first Jupiter from last month using the projection tube and a 25mm plossl.

[houston]

http://www.astronomysource.com/2011/10/13/eyepiece-projection/

Have a look at this site may help.

[budgierless]

I use a similar gadget made by revelation astro at half the price. It's excellent for planetary imaging using EP projection. It combines increasing image scale with an extension tube and can be used with and without the EP in situ. Best accessory I ever purchased.

Here is my first Jupiter from last month using the projection tube and a 25mm plossl.image.jpg

Nice, Can you post a link to the item you used, so i can review it please?

thanks

Phillip

[houston]

http://www.amazon.co.uk/gp/aw/d/B0039ZDYWY/ref=pd_aw_sbs_1?pi=SL500_SS115

Just ordered this. Worth a try.

[Owmuchonomy]

Nice, Can you post a link to the item you used, so i can review it please?

thanks

Phillip

http://www.telescopehouse.com/acatalog/info%5fBC018%2ehtml

[Owmuchonomy]

http://www.telescopehouse.com/acatalog/info_BC018.html

Note that my 15 and 25mm Celestron Plossls fit but my other EPs don't.

[budgierless]

http://www.amazon.co.uk/gp/aw/d/B0039ZDYWY/ref=pd_aw_sbs_1?pi=SL500_SS115

Just ordered this. Worth a try.

http://www.telescopehouse.com/acatalog/info%5fBC018%2ehtml

Ok, same item, well this seems like a good option, only thing missing is a t-ring, for that use, then good to go, i will add this to my wishlist.

thanks guys.

just to confirm this would be for a DSLR setup right? or webcam also?

and yes what about webcam if used, would i be better off trying to make my own modded cam or buy a custom built onemodded cam? any links would be helpful if buying is the suggested way.

Phillip

[budgierless]

Note that my 15 and 25mm Celestron Plossls fit but my other EPs don't.

I only have two at the moment, the stock EP and the 8-24mm EP, will that work do you think?

[Owmuchonomy]

Ok, same item, well this seems like a good option, only thing missing is a t-ring, for that use, then good to go, i will add this to my wishlist.

thanks guys.

just to confirm this would be for a DSLR setup right? or webcam also?

and yes what about webcam if used, would i be better off trying to make my own modded cam or buy a custom built onemodded cam? any links would be helpful if buying is the suggested way.

Phillip

I have no experience of webcam imaging just DSLR video for planets and long exposure for DSO.

[Owmuchonomy]

I only have two at the moment, the stock EP and the 8-24mm EP, will that work do you think?

The 25mm EP is the largest at 67mm long by 33mm wide. This just fits so that should give you an idea for your EPs.

[houston]

Oh dear. I have sold all my 1.25" eyepieces to buy all 2" fit. Still got the 10mm and 25mm that came with the scope.

[budgierless]

The 25mm EP is the largest at 67mm long by 33mm wide. This just fits so that should give you an idea for your EPs.

Yes!!!!, thankyou for confirming that for me, as i was thinking a issue was on the way, and was just reading about it and i thinking it wont work. nice one.

Phillip