Some long FL Ha from the other night

[multiweb (Marc)]

Shot a couple of weeks ago Friday night as it was a night of very good seeing in Sydney.

Got the motorized focuser now sorted out on the Mewlon 210. Guiding is still a bit iffy. I'm seriously considering using the AO on this one but I have to work out the spacing and back focus available.

Also got caught out on subs direction. 10min is too short. It was very noisy so I'm going to go for 20min next time at least.

I superimposed the pics to older Hyperstar shots showing the native FOV of the Mewlon in context.

Shot with a QHY9 and Baader Ha 7nm.

Enjoy the views.

[rustigsmed (Russell)]

looking good Marc - I like the Rosette. what is the FL ~2400mm?

cheers

[leon]

Very impressive Marc, keep at it mate.

Leon

[Rod771 (Rod)]

Very cool, Marc! The Mewlon produces nice detail.

[RobF (Rob)]

Looks like a great addition to your imaging stable Marc!

[Somnium (Aidan)]

the close up images look like a lot higher FL than 2800 (C11), have you used a barlow as well ?
well done at such long FL, to have the tracking that good is no easy feat

[Paul Haese]

Nice detail in the close ups. Well done Marc.

[Placidus (Mike and Trish)]

From what I can see of the detail in the trapezium - superb pinpoint stars - I reckon the Mewlon would be fantastic for craters on the moon.

[Stevec35 (Steve)]

Great detail there Marc!

Cheers

Steve

[RickS (Rick)]

Very cool, Marc. Would be interesting to see what improvement AO makes at such long FL.

[multiweb (Marc)]

Originally Posted by rustigsmed

looking good Marc - I like the Rosette. what is the FL ~2400mm?

cheers

Thanks Russel. Yes 2400mm, bit over F/11.

Originally Posted by leon

Very impressive Marc, keep at it mate.

Leon

Thanks Leon. Starting to get the hang of it slowly.

Originally Posted by Rod771

Very cool, Marc! The Mewlon produces nice detail.

Thanks Rod. It is quite sharp but a lot slower than the C11.

Originally Posted by RobF

Looks like a great addition to your imaging stable Marc!

Thanks Rob. Yes it's going to be great to do RGB on the field as it's quite portable.

Originally Posted by Somnium

the close up images look like a lot higher FL than 2800 (C11), have you used a barlow as well ?
well done at such long FL, to have the tracking that good is no easy feat

Thanks mate. Not too sure TBH. All pics are uncropped. I'll have to try to do the trap with the C11 without the corrector which is x0.8 to check the actual fov. The lodestar with the OAG is working fine. I just need to pay a bit more attention to balancing the rig.

Originally Posted by Paul Haese

Nice detail in the close ups. Well done Marc.

Thanks a lot Paul.

Originally Posted by Placidus

From what I can see of the detail in the trapezium - superb pinpoint stars - I reckon the Mewlon would be fantastic for craters on the moon.

Thanks Mike. I haven't played with the collimation yet. I suspect it's close but not 100%. Clear nights with good seeing have been too few to stuff around with the scope yet, but I'll get to it all in good time I'm thinking of getting one of those ZWO 174mm like Dennis when funds allow and dabble in a bit of planetary and moonage. I have a DMK but it's firewire and a bit tricky to use with the old laptop.

Originally Posted by Stevec35

Great detail there Marc!

Cheers

Steve

Thanks Steve

Originally Posted by RickS

Very cool, Marc. Would be interesting to see what improvement AO makes at such long FL.

Thanks Rick. I can get away without it at prime but if I use the Baader FFC on it I'll have to work out how to fit it in the backfocus. There is room but it will be tight.

[Dennis]

Lovely work Marc and well presented. Love the resolution and clean, tight, round stars.

Where are your diffraction spikes from the 3 vane Mewlon spider?

Cheers

Dennis

[multiweb (Marc)]

Originally Posted by Dennis

Lovely work Marc and well presented. Love the resolution and clean, tight, round stars.

Where are your diffraction spikes from the 3 vane Mewlon spider?

Cheers

Dennis

Thanks Dennis. Mine has 4 vanes but they only appear on the very bright stars. Have you got 3 on the 180?

[Dennis]

Originally Posted by multiweb

Thanks Dennis. Mine has 4 vanes but they only appear on the very bright stars. Have you got 3 on the 180?

Hi Marc

Yes – my Mewlon 180 F12 has 3 vanes and they can act as a focusing mask as attached file shows.

It cannot compare to the clarity and accuracy of a Bahtinov Mask, but you can easily see an out of focus situation develop as the night wears on, as the focus shifts with temperature changes, etc.
Cheers

Dennis