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gorann

Sh2-119 - first bicolor with the RASA 8

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The moon is out so time for NB imaging and I continue trying out my new RASA 8. The RASA 8 is an f/2 telescope so normal narrowband filters work poorly. So far I have only one of those dedicated high-speed filters (only Baader makes them) and I recently collected Ha from this object with the High-speed Baader Ha filter but I am still waiting for the High-speed Baader Oiii filter (apparently in production) and a high-speed Sii filter is on the way in the mail from Germany. Last night in desperation I put on my 8.5 nm Baader Oiii filter to se if I could get anything, and it turned out I got quite a lot of signal, and no annoying reflexes.

So here is the result of a Ha-Oiii imaging attempt of Sh2-119, the less well known nebula just "to the left" of the North America Nebula.

Ha in the red channel and Oiii in the blue channel, and I made a synthetic green channel by 50:50 mixing of the Ha and Oiii data. Then I tweeked the colours towards an RGB look. All done in PS except initial calibration and stacking in PI.

Ha: 69 x 5 min. Oiii: 30 x 5 min, so tatally 8.2 hours. ASI1600MMpro Gain 139, offset 50, -20°C. NEQ6 mount.

20200905-7 Sh2-119 RASA bicolor PS19smallSign.jpg

Edited by gorann
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4 minutes ago, gorann said:

The moon is out so time for NB imaging and I continue trying out my new RASA 8. The RASA 8 if an f/2 telescope so normal narrowband filters work poorly. So far I have only one of those and I recently collected Ha from this object with the High-speed Baader Ha filter but I am still waiting for the High-speed Baader Oiii filter (apparently in production). Last night in desperation I put on my 8.5 nm Baader Oiii filter to se if I could get anything, and it turned out I got quite a lot of signal, and no annoying reflexes.

So here is the result of a Ha-Oiii imaging attempt of Sh2-119, the less well known nebula just "to the left" of the North America Nebula.

Ha in the red channel and Oiii in the blue channel, and I made a synthetic green channel by 50:50 mixing of the Ha and Oiii data. Then I tweeked the colours towards an RGB look. All done in PS except initial calibration and stacking in PI.

Ha: 69 x 5 min. Oiii: 30 x 5 min. Gain 139, offset 50, -20°C.

20200905-7 Sh2-119 RASA bicolor PS19smallSign.jpg

There is nothing wrong with that!  I'm using normal NB filters with my Epsilon, and it seems ok so far, but I would like to buy a highspeed Ha filter and do a side by side comparison.

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That is stunning. V supernatural - the red clouds blowing away to reveal the glowing entrance to Valhalla?

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1 minute ago, tooth_dr said:

There is nothing wrong with that!  I'm using normal NB filters with my Epsilon, and it seems ok so far, but I would like to buy a highspeed Ha filter and do a side by side comparison.

I now think normal NB filters work as long as they are not too narrow in the bandwidth. My Oiii is a 8.5 nm filter. The 3 nm filters would probably not do so great at f/2. So at f/2, cheaper is better😉

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3 minutes ago, vineyard said:

That is stunning. V supernatural - the red clouds blowing away to reveal the glowing entrance to Valhalla?

Thanks a lot for that very positive Nordic comment! My obsy is just a few km from Valhalla😎

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That's a stunner Goran, probably your best yet.

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4 minutes ago, MarkAR said:

That's a stunner Goran, probably your best yet.

Thanks Mark! It is nice to make progress🙂

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Stunning image, and the RASA works well with cheaper NB filters, what is there not to like?

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5 hours ago, tomato said:

Stunning image, and the RASA works well with cheaper NB filters, what is there not to like?

Thanks Tomato! Yes, a lot to like with this scope and especially nice that filters are not a problem - maybe the Baader high-speeds are just broad bandwidth filters, and really should be their cheapest ones. They refuse to declare the bandwidth but I think an earlier batch of high-speed Ha filters were marked 10 nm.

I just processed a HaOiii on the Lion Nebula (Sh2-132) with the same setup that I will post shortly.

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