30.09.2022 AR3107, 3110 & 3111

[Rusted]

Wet, overcast and windy morning. Cleared to sunny periods after lunch. Grabbed my chance to capture AR3110.
Seeing fairly steady and modestly transparent. 8ms 88fps, Gain 128, 912x912, 50/1000 in AS!3, ImPPG, PhotoFiltre7.
Resized to 700x700 for the forum. Equipment used in my signature.

30.09.2022 14.11 150.10 60mt 2xb rsz 700.jpg (111.7 KiB) Viewed 536 times

30.09.2022 14.12.57 150.10 60mt 2xb rsz 700.jpg (132.44 KiB) Viewed 536 times

30.09.2022 14.16 150.10 60mt 2xb rsz 700.jpg (119.87 KiB) Viewed 536 times

[Rusted]

13.19 & 13.39 [UTC] 100/2000. The sun emerged from behind the cloud to show local flaring near AR3110.
Then gone again in 20 minutes more.

30.09.2022 15.19 150.10 60mt 2xb.tif 100.2000 rsz 700.jpg (130.56 KiB) Viewed 530 times

30.09.2022 15.39 150.10 60mt 2xb.tif 100.2000 rsz 700.jpg (119.02 KiB) Viewed 528 times

[Rusted]

Later still: Frame size increased to 1000x1000 100/1000 stacked.

30.09.2022 16.05 150.10 60mt 2xb rsz 700.jpg (138.25 KiB) Viewed 524 times

30.09.2022 16.17 150.10 60mt 2xb.tif 100.1000 1kx1k rsz 700.jpg (131.54 KiB) Viewed 524 times

[marktownley]

Nice results there Chris!

[Rusted]

Thanks Mark.

I do keep trying.

The Lunt 60MT etalon has been a revelation.
It is strangely insensitive to tuning though.

It doesn't suddenly darken at best tune like the PST etalon did.
The Lunt just becomes uneven in brightness across the frame.
It doesn't look out of focus and then suddenly sharpen like the PST etalon did.

I wind the Gain up a little and aim for most even lighting.
Then return the Gain to normal levels for capture.
That seems to be the way to achieve best tune.

I really ought to build a new OTA.
Where I have adjustable control over sag and tilt of the tail end.
A rigid OTA might even produce a more noticeable best tune.

I'd be grateful for anyone's direct experience of tuning a Lunt etalon in a 6" mod.
Does yours behave like a PST etalon but with a much wider sweet spot?

[marktownley]

In simple terms the size of the sweetspot is proportional to the size of the objective to the size of the etalon in the collimated beam. So your 60MT mod will have a larger sweet spot.

Your next step to optimising it further, and in your instance getting a more even field and maximsing the available sweetspot size, would be to closer match the f ratio of your scope to the native f-ratio of the collimating lenses. Your scope is f10, the collimator f7. Try putting a 2" reducer close as possible to the collimating lens on the 60MT mdoule, this will make the Lunt module see a beam that is closer to the f7 that would be the ideal.

[Rusted]

Thank you mark Mark. All useful information.

Having had no personal experience of focal reducers can you point me at a suitable candidate?
Does price match quality in this application?

Thanks again.

[marktownley]

Personally, I think all the '0.5x' reducers are much the same thing so go for what is available locally.

Is it easy enough to attach to the 'snout' of the 60MT?

[Rusted]

Okay. I'll order a T-S 2" 0.5x focal reducer.

I shall be screwing it to the original MT nosepiece behind the 2" Baader/Beloptik filters.

Thanks again.

[ffellah]

A very nice set Chris !

Franco

[Rusted]

Thank you Franco.

Chris

[DeepSolar64]

Nice flaring captures, Chris!

[Rusted]

Thanks.

[Rusted]

Nice images Chris, a lot of nice details captured.

Thanks very much.

[MAURITS]

Nicely done Chris, beautiful detailed images.

[arnedanielsen]

A fine set Chris!

Best regards,
Arne