95 replies to this topic

[ghataa]

More

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[ghataa]

More 3c

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[ghataa]

More 3c pic

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[ghataa]

More 3c pics

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[ghataa]

3s

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[ghataa]

3s more

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[ghataa]

3s last

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[saemark30]

What coatings does the Tair 3c have, single or MC?

[Falcon-]

So... I got curious due to the fact that the "3c" is written in cyrillic while the "3s" is not.

Turns out if you type "TAIR-3s" into cyrillic you get "ТАИР-3c". I suspect the 3c and 3s are the same thing translated. Makes sense given how close to each other they seem to be.

That still leaves three versions:
- the 3a (newer standard lens form factor)
- the 3s/3c (gun stock mount form factor)
- 3? (original older standard lens form factor)

with slight variations in each type over time such as ghataa's two show.

[dp297]

Interesting practical detail....the Tair 33 I got does not have the standard screw size underneath (the same size as the one underneath Canon 350D)..meaning that the required bolt might be thicker and that could create problems.
For example it might be too thick to fit the plate I have and are planning to use as a dual platform.
How did you cope?

[Falcon-]

Interesting practical detail....the Tair 33 I got does not have the standard screw size underneath (the same size as the one underneath Canon 350D)..meaning that the required bolt might be thicker and that could create problems.
For example it might be too thick to fit the plate I have and are planning to use as a dual platform.
How did you cope?

I did totally forget to mention that small detail. I suspect what dp279 is seeing is a 3/8-16 standard tripod screw. Wikipedia tells me that traditionally larger lenses and cameras tended to use the 3/8-16 instead of the more common smaller 1/4-20 screw.

There are screw on adaptors that allow you to chance back and forth between 1/4-20 and 3/8-16 and it just so happens that the top of the ball head I had for my side-by-side camera mount plate could be reversed to work either as 1/4-20 or 3/8-16. That made it easy for me.

With my particular examples I find:
- The Tair-3a has both 1/4-20 and 3/8-16 socket in it's tripod collar foot
- The Tair-3s has only a 3/8-16 socket

[dp297]

An adaptor it is then...thanks.

[ghataa]

Here is my first iteration of the Dual Tair rig. I feel limited by the Nikon (software, filters etc) but hooked it up as a test run and took some subs. Will most likely pick up another Canon for the ease of use of BYEOS and the clip-in filters I already have.

I mainly focused on the Ha last night given the brightness of the moon and the overall light pollution to the north (NYC). Generally I found the rig to be stable but did lose some subs due to the CG5 hitting a little rough patch for a few subs.

I used the Tair 300mm at 5.6, ISO 400, with 5 min subs.

Here is 45 min of the butterfly nebuala.

George

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[ghataa]

Butterfly test with Tair at 5.6

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[ghataa]

I tried out the dual rig last night with two T3i and could not achieve focus. Hmmmmm. The picture above was using a Ha filter and apparently the optical chain is altered enough by the filter to allow critical focus. I did try the EOS CLS clip-in filter but that didn't help and the stars were out of focus even at "infinity". I did try a Nikon D7000 which uses a different adaptor to connect to the Tair and I could achieve focus. However, my light polluted sky prevents routine use of the D7000 with the Tair. I could use this as a platform for just narrow band but would like the flexibility do to full color as well.

I will try Alex's trick tonight and see if I can find and loosen the screw that will allow focus beyond infinity.

Any other ideas about how to alter the path to achieve focus for wide spectrum acquisition? A differnt EOS mount adaptor perhaps?

Thanks,

George

[avarakin]

George,
I received my M39 to Canon adaptor and I can see that it is thinner that T adaptor I was using previously, so it may help you to achieve better focus. I got it from ebay for about $5 from China, let me know if you need a link.
If you need it badly before vacation, I can lend it to you - I am in Parsippany NJ.

I don't know if it is problem with my lens, but I finally figured out yesterday while doing some test shots that CLS filter does not work well with this lens: If I remove it, I have reasonably nice images with very little CA. If I install it, I am getting really bad purple fringes around brighter stars.

On the other hand, images with OIII and Ha filter are extremely sharp.

So if I were you, I would buy an Astronomik OIII filter and then shoot OIII and Ha at the same time; and then combine them into false color images like this:

http://www.astrobin.com/full/7605/A/?



Alex

[ghataa]

Hi Alex,

Thanks for the offer. However, I may have solved my problem. I noticed this morning that there are 3 tiny set screws holding a plastic ring on the end of the lens near the glass. In the pics above, it is the ring that has the "Tair3c 4,5/300" label. By removing the set screws I could extend focus even further as this hard stop was removed. I gained about an extra 1/4 inch for the lens tube to retract so I hope that is enough. I can certainly focus further on a distant tree branch than with the ring attached. I will test tonight if the sky is cooperative!

George

[ghataa]

Removing those rings did the trick. I can easily achieve focus with or without clip in CLS or Ha filters.

Of course my CG5 acted up and I had guiding issues that were self-inflicted. I had to remove one lens and forgot to rebalance after putting it back.

George

[D_talley]

I enjoyed reading your experience with the Tair lens. I have the Tair 33 which was attached to my mamiya 645 medium format camera. Found an adapter, the fotodiox pro that lets me connect it to my Canon T1i.

The attached shot was a test with the lens. 10 x 120 seconds using the standard camera at 1600 iso. My next test will be longer and using a modified camera.

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[ghataa]

Hi Dwight,

Very nice Orion and Running Man. It is surely a very capable lense at a very affordable price. What f stop did you use?

Best,

George

[D_talley]

Thanks. I was using f 5.6 but should drop down between 5.6 and 8 to see how the stars do.