The Power of F2 : HorseHead Nebula in 90mins

[Catanonia]

This is why I love the RASA8 in the UK

With the very limited time on target due to English (North West) weather, every second counts and a F2 scope with OSC makes this possible in 90mins, especially in Bortle 6 skies

I was constantly dodging the clouds and some subs have cloud in them that stopped me really getting some of the nebula.

Details

• Bortle 6 Skies in NW of England
• RASA8 on EQ8 mount
• ZWO 2600 MC Pro OSC main camera with 120mm guide  (No filters)
• ASI Air Pro
• Toe nail moon
• 90 mins in 3 min unbinned subs (then resampled to 2x)
• PixInsight processed with BlurX and Spectral Colour Calibration

 

Edited February 25, 2023 by Catanonia

[Paul M]

Talk about taking it to the next level!

That's astounding. Not that it's any of my business but I'm pleased to see Alnitak in all its glory 😍 

[tomato]

 Very nice, how do you get the 4 big spikes on the bright stars?

[Catanonia]

Just now, tomato said:

 Very nice, how do you get the 4 big spikes on the bright stars?

On the front of the RASA 8

Cable router from Steve Morris 

[ONIKKINEN]

Lovely, i really like the diffraction spikes. Adds character to the stars that is sometimes missing from RASA images where the stars are very much a secondary part of the image compared to the not-stars part.

[callisto]

Excellent image 👌

[gorann]

Great image, especially for 90 min, and you really reinforced the original selling argument from Celestron when they introduced the RASA line. And then, when you finally get a long clear night - aim it for something faint and it will blow you away (with or without star spikes)!

Edited February 25, 2023 by gorann

[MKHACHFE]

Holy moly. That is absolutely stunning work mate. Kudos to you.

Cheers 

[Catanonia]

On 25/02/2023 at 22:44, gorann said:

Great image, especially for 90 min, and you really reinforced the original selling argument from Celestron when they introduced the RASA line. And then, when you finally get a long clear night - aim it for something faint and it will blow you away (with or without star spikes)!

lol, is only Celestron would pay me  Thank you and would love to take the scope to a proper dark sky.

On 26/02/2023 at 07:00, MKHACHFE said:

Holy moly. That is absolutely stunning work mate. Kudos to you.

Cheers 

thank you, was surprised  how well it came out for 90 mins

On 25/02/2023 at 13:47, Paul M said:

Talk about taking it to the next level!

That's astounding. Not that it's any of my business but I'm pleased to see Alnitak in all its glory 😍 

Thank you, appreciated

On 25/02/2023 at 15:52, callisto said:

Excellent image 👌

Thank you

[alpal]

What an amazing picture to get in only 90 minutes.

That shows the power of f2.

How could it be better? -

3 minute exposure have most likely hit the well depth on most of the stars -

maybe a short exposure of say 30 seconds used and then the stars copied and pasted in to get more colour in the stars?

cheers

Allan

 

 

[MKHACHFE]

I just wanted to say that I came here to read the reply to what I posted the other day and was just blown away yet again by the image you posted. I'm almost inclined to not believe you about it only being 90 mins of subs! 😄

I'm totally joking of course. You clearly set up the camera, polar aligning, focus etc absolutely perfectly... and it shows. Amazing, seriously.

Not to hijack your post, but this is my first and only attempt at this target. It was, to be fair, only about 40 mins of lights, and done with a 300mm f/5.6 and unmodded cam and a Star Adventurer Mini,  and it was taken when i just started out in AP a few years ago. It WAS however from a Bortle 2 site near Glencoe ( i just took some at the end of my session to see if I could get anything). 

Im still proud of what i got that night, but your image has inspired me to try again the next chance I get.  I'll have to borrow my brother's F2 lens. 

👍👍

 

Edited March 4, 2023 by MKHACHFE
details and spelling

[Catanonia]

On 04/03/2023 at 01:56, MKHACHFE said:

I just wanted to say that I came here to read the reply to what I posted the other day and was just blown away yet again by the image you posted. I'm almost inclined to not believe you about it only being 90 mins of subs! 😄

I'm totally joking of course. You clearly set up the camera, polar aligning, focus etc absolutely perfectly... and it shows. Amazing, seriously.

Not to hijack your post, but this is my first and only attempt at this target. It was, to be fair, only about 40 mins of lights, and done with a 300mm f/5.6 and unmodded cam and a Star Adventurer Mini,  and it was taken when i just started out in AP a few years ago. It WAS however from a Bortle 2 site near Glencoe ( i just took some at the end of my session to see if I could get anything). 

Im still proud of what i got that night, but your image has inspired me to try again the next chance I get.  I'll have to borrow my brother's F2 lens. 

👍👍

 

I too was amazed that I got this in 90 mins. 

What you have to remember is the RASA8 is a "proper" astrograph with a cooled dedicated astro camera ZWO 2600 MC Pro. Along with its F2, the image was then resampled in software to effectively give it a 4x on F2 which is amazingly fast.

In your image, stars are bloated and I suspect poor guiding and focus, but as you said, you were testing kit out., but either way, it is how it make you feel which is all that counts.

I recon you could do MUCH better now you have experience under your belt.

Don't bother on borrowing lenses, concentrate on the basics , F2 is much less forgiving and unless you have the basics of guiding and focus, it will be frustrating to say the least.

Edited March 7, 2023 by Catanonia

[MKHACHFE]

On 06/03/2023 at 08:37, Catanonia said:

I too was amazed that I got this in 90 mins. 

What you have to remember is the RASA8 is a "proper" astrograph with a cooled dedicated astro camera ZWO 2600 MC Pro. Along with its F2, the image was then resampled in software to effectively give it a 4x on F2 which is amazingly fast.

In your image, stars are bloated and I suspect poor guiding and focus, but as you said, you were testing kit out., but either way, it is how it make you feel which is all that counts.

I recon you could do MUCH better now you have experience under your belt.

Don't bother on borrowing lenses, concentrate on the basics , F2 is much less forgiving and unless you have the basics of guiding and focus, it will be frustrating to say the least.

Yeah. The stars are very bloated. The canon 70-300mm f5.6 i used can be quite tricky to focus. So much so that i sometimes choose less than perfect focus over fiddling with it for another 30 mins. The difference between sharp and bokeh with this lens is such a slight turn of the ring that i can barely feel the motion of my hand 😶

No guiding there either. That was not something in my repertoire yet. 

Cheers 

[Catanonia]

3 hours ago, MKHACHFE said:

Yeah. The stars are very bloated. The canon 70-300mm f5.6 i used can be quite tricky to focus. So much so that i sometimes choose less than perfect focus over fiddling with it for another 30 mins. The difference between sharp and bokeh with this lens is such a slight turn of the ring that i can barely feel the motion of my hand 😶

No guiding there either. That was not something in my repertoire yet. 

Cheers 

Then stay clear of F2, this will make this more difficult as F2 is very unforgiving.

If I were you, I would look at getting some guiding sorted and move from there

[900SL]

On 25/02/2023 at 15:39, Catanonia said:

This is why I love the RASA8 in the UK

With the very limited time on target due to English (North West) weather, every second counts and a F2 scope with OSC makes this possible in 90mins, especially in Bortle 6 skies

I was constantly dodging the clouds and some subs have cloud in them that stopped me really getting some of the nebula.

Details

• Bortle 6 Skies in NW of England
• RASA8 on EQ8 mount
• ZWO 2600 MC Pro OSC main camera with 120mm guide  (No filters)
• ASI Air Pro
• Toe nail moon
• 90 mins in 3 min unbinned subs (then resampled to 2x)
• PixInsight processed with BlurX and Spectral Colour Calibration

 

That's really quite something. How do you manage 3 minute subs at f2 in bortle 6 without overexposing everything?

[Elp]

I can barely do 20 seconds at f2 so am wondering the same. Regarding issue with f2, I don't really see why people consider it difficult, it's not any different from normal imaging in my experience.

[Catanonia]

1 minute ago, 900SL said:

That's really quite something. How do you manage 3 minute subs at f2 in bortle 6 without overexposing everything?

Not sure, I know that 4 mins is too much and I don't like doing 30s subs, so long time ago plumped for 1xbin 3min subs as a default and then 2x bin in software.

To be honest, I not looked too deeply at the sub saturation, just played it by eye.

If I am doing something bright, like M42, I will reduce it down to 1 min 1xbin subs and then combine with some 3m 1xbin subs for the outer regions.

Not using any filters either

[900SL]

4 minutes ago, Elp said:

I can barely do 20 seconds at f2 so am wondering the same. Regarding issue with f2, I don't really see why people consider it difficult, it's not any different from normal imaging in my experience.

I suppose the biggest issues are focus and tilt, given the wafer thin depth of field.

[Elp]

That is very odd indeed. My HS usually saturates completely to white in 30 seconds. Only pointing north or west I can get away with around 60s but the centre of the image is usually close to white but not clipped. This is from a bortle 7 zone.

[Catanonia]

Just now, 900SL said:

I suppose the biggest issues are focus and tilt, given the wafer thin depth of field.

Correct, these 2 are the biggest problems.   The guiding has nothing to do with it, this was just be advising the previous member who posted his picture, not to bother with F2 and concentrate on the basics, ie get some guiding.

The amount of tweaking I had to do to my RASA was ripping my hair out until I was forced to strip it to clean out water increase.  This forced me to learn how to collimate the RASA 8 and the OCAL collimator is extremely useful for this.

[Catanonia]

1 minute ago, Elp said:

That is very odd indeed. My HS usually saturates completely to white in 30 seconds. Only pointing north or west I can get away with around 60s but the centre of the image is usually close to white but not clipped. This is from a bortle 7 zone.

I am using a ZWO 2600 MC Pro OSC which has a deep well depth. Wonder if that helps

Edited March 8, 2023 by Catanonia

[Catanonia]

4 minutes ago, Elp said:

That is very odd indeed. My HS usually saturates completely to white in 30 seconds. Only pointing north or west I can get away with around 60s but the centre of the image is usually close to white but not clipped. This is from a bortle 7 zone.

I have attached a 1xbin 3minute FIT sub of  the cone nebula I took last night. The full moon was still low down and got away with it for about 40 mins

Light_Debeyers_180.0s_Bin1_20230307-191801_0001.fit

Edited March 8, 2023 by Catanonia

[Elp]

3 minutes ago, Catanonia said:

I am using a ZWO 2600 MC Pro which has a deep well depth. Wonder if that helps

Likely though it might be more to do with how the light is spread out over a larger pixel area, some of my 294 images are 60s exposures and that has a similar FWD.

[900SL]

I've quite fancied a RASA as clear nights here are few and far between, but shied off given some of the horror stories I've read about Celestron QC. How have you RASA 8 owners found them (apologies for the slight side track.. I have ADD  

[Catanonia]

21 minutes ago, Elp said:

Likely though it might be more to do with how the light is spread out over a larger pixel area, some of my 294 images are 60s exposures and that has a similar FWD.

For giggles, last year I took a single 2x bin single10min sub on the RASA8 (with a lEnhance filter in place) and then processed it as best as I could in PI.

10min FIT sub attached if you want to look and play (this did not have the cable router in place and hence the stars have no spikes, rather cable loops. Also the collimation was off along with 10mins 😃 bad star shapes)

Light_IC434_600.0s_Bin2_0002.fit

Edited March 8, 2023 by Catanonia