Eta Carinae

[Sunfish]

The cold seems to change the focus on my old f8 ed 800 lense even after I have locked it down.

I think I need a belt and a motor. Maybe a heater. And the Bahtinov does not work on the faint stars. Only four one minute shots stacked.

[multiweb]

Looks very good for a lens shot, no chromatic aberration. With lenses I tend to focus by the numbers. As you've pointed out the aperture is too small to use a bahtinov mask effectively. Using Nebulosity and picking a bright star you can check the numbers and focus accurately this way provided the seeing is not too bad. Then I tape the barrel of the lens with electrical tape across so it locks it in focus, then stick a pack of hotties on top and bottom then finish off wrapping it with a sock. That usually gives me 8h to 10h of passive heating and that's good enough to last the night.

[Sunfish]

Thanks Marc. I will try some warmers. The nikkor ed is a great lense and the focus locks with an adjustable click knob if you don't handle it. But I could add tape to save the bumps.

I have made a Bahtinov with fishing line like a tennis racket ( after a East European design) which works on the lense on bright stars at full live zoom Problem is focus changes over time but the warming and the taping might help. Once I have found the target I don't want to move to check.

And then a radio so I don't miss the World Cup out in the dark. Close match this morning.

[multiweb]

Looking at your lens design I'd keep the warmers at the end where the glass is then wrap the rest of the exposed length with a layer of socks. It's likely it shortens when it gets cold.


Yeah very good game, extremely close. The goal keepers certainly earned their money.

[ChrisV]

Looks good for a single sub.
And we got a goal against France - Belgium didn't.

[xelasnave]

Nice capture Ray.
Dont stop firing until its gone.
I cant get it from here because of trees.
I like Marcs ideas.
I like a baffeld dew tube but Marks idea would be great to add..
I use blue tack to hold the lens in place and to secure cables to the camera so pressure on the connections is never an issue.


I think the key is doing it as muuch as you can with what you have ..only today I found stuff I could do in two different programs that moves the game forward...I an happy what I can get with free software... I love camera and lens approach...I have plans for a double camera widefield rig.
Do what I can with the cheap lens I have.


Great work.


alex

[Sunfish]

Two different stack modes for the same image. Ten images of about a minute each this time. One mean stacked after importing into lightroom PS after a few adjustments and one stacked in DSS. Overall better than four stacked images? Maybe a little.

For these shots PS was much easier and looks more like what is visible with a lot less bother. DSS recognises the camera model and does whatever is required I imagine with the PS imported dng, but looks washed out and I still have to go back to PS and get the colour back to the same position.

[xelasnave]

Looks good to me.
Have a look at the debayer thread as you may need to make adjustments to DSS. You may have it covered but worth a look.
alex

[Sunfish]

[QUOTE=multiweb;1383653]Looking at your lens design I'd keep the warmers at the end where the glass is then wrap the rest of the exposed length with a layer of socks. It's likely it shortens when it gets cold.

Yep. There is a lot of steel and glass in that lense. More than 2kg of it. Need to get the gloves on to touch it at after a few hours at 7 degrees so shrinkage could definitely be a factor. Maybe 0.3 mm.