Attention Nikon DSLR users, your help needed.

[radiostationx]

Hi ,

I wonder if any member may be able to help.

I have a different application for the use of a telecope so please see my post in the welcome section which you may find interesting.

http://stargazerslounge.com/welcome/163427-hello-all-sgl-newbie-new-angle-telecopes.html

I am keen to learn from you Ladies and Gentlemen who know a thing or 2 about telescopes, astrophotography and such things.

I know that members must be fed up with people asking this one but here goes…

I am very keen on aircraft photography ,I own six Nikon digital reflex cameras and a bunch of bits of glass to stick on them accumulated over 30 yrs.

At the moment I have been using 400mm f5.6 tokina lens which on dslr gives 600mm aprox focal length, but its not close enough for me..

I have to crop picture to get anywhere for a usable photo.

I am in the north west England and local to busy high level transatlantic air routes.

I am keen on purchasing a skywatcher skyliner 200p (8 inch) Dobsonian.

Theoretically this gives me 1200mm @ aprox f 6 on the cheap !

I am a little confused as to how the Nikon will focus at infinity when liked to the scope.

Nikon cameras have a different reference distance (sensor to lens mounting flange distance) than canon.

It differs by around 2.5mm in each case.

Canon reference distance is 44mm and Nikon is 46.5mm.

I am told that when a Nikon is mounted on the scope there may be problems as there will not be enough inward travel from the focuser to get infinity focus.

What is done to overcome this problem ?

This is the reason why canon users can use nikkor lenses with a straight adaptor ring in manual mode but Nikon owners cannot use canon lenses without an adaptor which has a glass converting element/s inside.

These are usually very low quality and have an adverse effect on image quality.

Scenario 1 :

Prime focus when Nikon is attached to the scope tube by removing first the 1.25inch adaptor which reveals a direct connection for a camera.

Do I need a Nikon to T2 adaptor like this

Telescope T2 Mount For Nikon D3X, D3, D700, D300 Nikon: Amazon.co.uk: Electronics

However please note in the technical details section the warning about focus.

What does this mean ? It wont work ?

Im confused dot com !

Or a T adaptor like this :

First Light Optics - T Rings

Just what is the difference in a T adaptor and a T2 adaptor ?

The pitch of the thread ???

Which one do I need for attaching to the skywatcher scope focuser in direct slr connection mode ?

Scenario 2:

Most photographers for this photography application use a 2x 2inch Barlow lens to get real close on an aircraft which is distant .

The adding of a Barlow will change the focus/eyepoint bringing it further out of the scope? Am I correct ?

A 2 inch model is used to allow plenty of light into the sensor.

I have heard that some changes have to be made to the Barlow lens to achieve focus properly with Nikon cameras namely by changing its physical length in some way by removing part of the outer shell.

I am considering also a 2x ed glass Barlow lens which seems very similar to soligor 2x Barlow used by skystef some time ago at the bottom of his very informative page here .

Weather & Aviation Page - Contrail telescope setup

Unfortunately for me, skystef from Belgium has a canon camera and a 2 inch soligor barlow !

Current equivalents/clones to the Barlow he uses are feautured below.

It appears they are made by GSO,and it appears that soligor is indeed a gso clone and It appears in several guises with a 1.25 adaptor which will be discarded for my intended purposes.

Revelation ED 2x Barlow 2"

it seems the same one as this

http://www.amazon.co.uk/TS-Optics-Barlo ... B004ORX50C

Are there any photographers here who use Nikon cameras,and if so could they perhaps post a few photographs of their setup particularly the camera to scope attachments for lunar photography.

This would be extremely helpful to me as I would not like to purchase scope and find it will not work with my camera.

Searching the internet reveals very little indeed, Canon is king for people with telescopes it seems !

I do not wish to change camera as I have used Nikon for 30 yrs.

There must be someone out there using Nikon .

I have heard also that moving the primary mirror further up the tube can assist with focusing but I would be flummoxed with that .

At the moment my shopping list is :

200mm dobsonian scope

2 inch ed Barlow.

Connecting pieces/metalware for scenario 1 and 2 ( currently taking expert advice from SGL ).

Dear successful Nikon astrophotographers with Skywatcher Newtonians/reflectors…

I see your moon pictures on SGL, very nice !

Could anyone post some pictures of their Nikon attached to a skywatcher newtonian/dobsonian for lunar photography (they have a common crayford type focuser with direct slr connection) together with the various bits/hardware I need ?

This will help me a lot.

Sorry it’s a long post with lots of links but any advice appreciated.

[Tinker1947]

With my D80, i use the manual setting this sets the shutter speed and aperture, it also turns off automatic focusing, which is what i suspect you need..the DSL uses a T Connector, this screws into a 1.25/2" reducer as the Skywatcher has a 2" focuser, Steve at FLO sold me the bits i have.

[x6gas]

Hi there,

You'll need a Nikon t-ring to couple your camera to the scope. The t-ring has the Nikon bayonet fitting on the camera side and an M42 0.75 t-thread on the scope side. The t-thread will screw directly to the draw tube in the SkyWatcher 'scope which will allow enough focus travel for infinity.

I don't have much experience with using a barlow for photography. When I do, I have a 1.25" (one of the standard sizes for things that drop into the focuser drawtube on the scope) and then have a t-adapter which slots into the drawtube (not threaded, it's held in place with thumb screws which is not my preferred route) and has an M42 male thread which then attaches to your camera via the Nikon t-ring. With the barlow there should be no problem reaching focus using the telescope's focuser, so you shouldn't need to modify the barlow. Same would apply if you wanted the greater clear aperture offered by a 2" barlow.

Can't help you with how you'd track an airplane in flight with a Dob, but I am sure it can be done!

Hope that this helps...

[chiltonstar]

I use my Nikon D300 on several scopes (600mm and 1500mm "focal length").

Set the camera on "M", couple via a T adaptor and play with the exposure until the result is what you are looking for. The biggest problem is likely to be camera shake, as you have a very long "telephoto" if you use a scope - you will need an exposure of 1/1800 secs or less if you want to avoid it. Best also to use the mirror lock up facility to reduce the problem.

Chris

[radiostationx]

With my D80, i use the manual setting this sets the shutter speed and aperture, it also turns off automatic focusing, which is what i suspect you need..the DSL uses a T Connector, this screws into a 1.25/2" reducer as the Skywatcher has a 2" focuser, Steve at FLO sold me the bits i have.

understood and thats how i expected.

I take it that you remove and discard for photography purposes the 1.25 to 2 inch eyepiece adaptor that skywatcher give you for free with the scope.This reveals a convienient thread at the top of the focuser draw tube for you to connect to.

Then its the bits you have that i am interested in

The Nikon fit t ring is this correct

First Light Optics - T Rings

Is this a T ring or a T2 ring or are they the same thing ?

Does this "click lock" into place on the nikon f mount like a lens does or does it continue to rotate if turned until it disengages every 60 degrees of a turn like cheap extension rings do?

In theory ,This mated to the focuser directly will get the camera sensor closer to the secondary mirror.

Can you achieve infinity focus using only this part between camera and scope or do you need another part to do this ?

[Astrokev]

I suspect only those with the same scope as you will be able to say whether you can achieve focus with your DSLR.

What you're trying to do will depend on exactly how far the focal plane is from your focusser when fully racked in, and whether this is enough to enable the DSLR sensor to be able to attain this point. If it can't I think your only option is to move your main mirror up the tube (or secondary & focusser down the tube).

Once you can achieve focus, the next challenge is getting good focus. Without the use of the DSLR AF, you'll have to use manual, as others have said, which is more challenging.

Tracking the airplane should be possible, though will probably need lots of practice to get the shots you're after.

Good luck though - if you can do it, you'll get a real buzz.

[Dave]

understood and thats how i expected.

I take it that you remove and discard for photography purposes the 1.25 to 2 inch eyepiece adaptor that skywatcher give you for free with the scope.This reveals a convienient thread at the top of the focuser draw tube for you to connect to.

Then its the bits you have that i am interested in

The Nikon fit t ring is this correct

First Light Optics - T Rings

Is this a T ring or a T2 ring or are they the same thing ?

Does this "click lock" into place on the nikon f mount like a lens does or does it continue to rotate if turned until it disengages every 60 degrees of a turn like cheap extension rings do?

In theory ,This mated to the focuser directly will get the camera sensor closer to the secondary mirror.

Can you achieve infinity focus using only this part between camera and scope or do you need another part to do this ?

Yes, that is exactly what you need to reach focus. Unscrew the inch & quarter adapter and screw the T-ring (and camera) directly on.

Have fun.

Dave

[radiostationx]

Thanks nikon users.Thats prime focus sorted (scenario 1)..But I still dont know if its a "Nikon to t adaptor ring" like this

First Light Optics - T Rings

or a "Nikon to t2 adaptor ring" like this

Telescope T2 Mount For Nikon D3X, D3, D700, D300 Nikon: Amazon.co.uk: Electronics

And dare i ask Whats the difference ?

Also do these things "click lock " onto the mount as a lens would ?

I see the intentation on the camera flange side on the featured (canon) one from FLO, above the n in the canon lettring.

I hear what you are saying astrokev regarding tracking a plane it is not easy and thats why it is indeed "extreme spotting" with the emphasis on extreme !

The method is to find contrail in the finder scope, quickly swap to camera viewfinder and follow the contrail by guiding the scope along it to the aircraft.

People who do this hobby fire off perhaps 30 shots on an aircraft pass,one hand on the top edge of scope tracking gently the other alternates quickly between shutter button and focuser barrow .

it is normal to get 20 into trash bin/delete they will then pick the best of those 10 which are left/ usable.

[x6gas]

I think there is some technical difference between a t-ring and a t2 ring - possibly something to do with being able to decouple the bayonet fitting from the t-thread - but there is no practical difference. I have one which is one piece and very low profile, works fine...

The t-ring will indeed click lock on to the camera body.

[Tinker1947]

I checked my Invoice and it lists a " Model SW _2_inch_T_Adapter" next line,"Skywatcher 2 inch T Adapter" cost £17.50 plus VAT, This adapter breaks into 2 parts, a extension tube and the adapter they screw together, so i don't use the extention tubes the Nikon has the " http://www.firstlightoptics.com/adaptors/t-rings.html " fitted connects just like a lens, this then has the 2 inch adapter screwed into it, the other end of the adapter has a 2" extension which goes in the focusers and is held in place by the 2 thumb screws, this adapter is only about 1/2" in length and focuses with no problem