Clarkey

Perhaps Roboscopes needs a RASA.😁

Maybe we should suggest it....

I suspect they are staying well clear due to the time taken to set it up.

High humidity can cause the glow round the brighter stars. Sometimes tricky to process whatever you do.

If you create a starless version in PI, then part stretch the starless image until just before the halos appear. You can then use the GAME script to mask the background whilst stretching the galaxy a bit more. (You can also use the blend tool to add back the stars and adjust the black/white point to keep the background clean). Might be worth a go?

Great image. (I have something to aim for now. I am part way through imaging this at the moment using a remote rig in Spain. If it looks as good as yours, I will be happy).

8 hours ago, Vroobel said:

Thank you. 😊 I also like these colours, though some people say that more explicit colours would add more space and depth to the image. I should try both ways next time. 🤔 😄

I think the slightly muted colours are the right way to go. I have done a lot of the Adam Block tutorials, and much as he knows what he is doing, I find his colours too strong. This is a really nice balance. Cracking image.

1 hour ago, Giles_B said:

I think appearances may be deceptive - the camera UV/IR window is sitting directly on top of the prism stalk

Must be a long prism stalk.....

Looking at the picture the bottom of the camera definitely looks quite a long way out compared with mine.

I'm not sure who said not to use the 120 mini. Yes, they are a little old now and the 220 will undoubtedly have a better QE, but they still work. I upgraded to a 290 which is marginally bigger - but here is not much in it.

47 minutes ago, Oddsocks said:

Maybe a cheaper solution that replacing the entire OAG would be to find a simpler T2 attachment for the guide camera coupling instead of the Baader mechanism that is currently pushing the guide camera too far out so that you can't reach focus

Agreed. The camera is a long way from the prism. If you get rid of the Click-lock and add a micro-focuser it is much simpler.

4 hours ago, Oddsocks said:

Not sure that you need to specify such a big prism requirement for a 975mm FL OTA

Also, I would agree with this. I am using a 'standard' prism and 120mm mini at 1000mm and I have used a similar set up at 1200mm FL without issue.

Technically you can use figures from software to give you an idea, but this is affected by guiding and focus. For me it is simple. 95% of the time my seeing is OK, the rest is poor except one night per year when it is good. I should add that I do not image from May to August so I can't comment on summer figures.

Run the guiding assistant and it will measure your backlash. It looks quite bad. Also, it will help with other settings.

1 hour ago, 900SL said:

I quote '

Peltier cooling: The lifetime limiting parameter on most metal to ceramic bonds is the number and magnitude to thermal cycles. The higher the delta T, the shorter the life. A rule of thumb is that for every 10 degrees centigrade, lifetime gets cut in half'

Also thermal shock may be higher on disconnection. Plus, and this may be more important,  if you run maxed out, any further drop in temperature may change the sensor temp as the peltier has nothing left in reserve

There was also some debate as to whether the 2600 oil-on-sensor issue was exacerbated by running coolers at 100% in hot climates

A quick google search will throw up some data.

My take is to err on the side of caution. However, because I live in finalnd, I often cool to -30C as it is only delta 15C   When I was in Saudi I didn't go below 10C 

Ok thanks. Interesting to know.

10 hours ago, 900SL said:

it is not advisable to operate for length at more than 80% cooling

This is a new one on me. Where is that from? Surely the manufacturers would design to allow full cooling without damage to the camera? Personally, I never get near to 100% as I do not image in the summer, but inquiring out of interest.

Great image once again. I agree with @Nik271, stationary targets are definitely my forte!

Auto tracking - now that will be impressive if you pull it off with the Dob. I assume you got your motor problem sorted?

1 hour ago, Stephen196360 said:

40cm x 40 m square

Blimey, how big is your scope?

1 hour ago, ollypenrice said:

In this case I do think the reflector star spikes are an issue since they dominate part of the nebulosity - but that's not your fault.

I know. Us poor folk who can't afford 12" refractors🤣

1 hour ago, ollypenrice said:

As for the green-blue balance, we know that OIII lies on the blue-green border, often known as Teal Blue. I'd up the greens a bit, but that's me

Boosted the green a bit - had trouble not messing up other part of the colour balance and making it look 'natural' without starting from scratch. No sure which version I prefer though...

11 minutes ago, WolfieGlos said:

Nice job, and the detail in the core is superb. It almost looks like a mini Ring Nebula in there.

I've not imaged this one before, but a lot of images show it a lot greener, perhaps they are over-saturated maybe? I quite like this one 🙂

Thanks for the comment.

The core was the difficult bit. I used 1 min subs, but they really needed to be 30 seconds or less. Trying to get the detail from an over-exposed image was tricky. I ended up merging the RGB data with the 60s narrowband in the core, then blending this into the outer ring.

You might be right regarding the colour, but I was working on the predominantly blue from the strong O3 signal. There is a little Ha, but it is pretty faint. 

Probably the hardest image to process I have done so far. The core is very bright, but the out regions are pretty faint. Anyway, this is about 8 hours of data, mainly O3 and Ha with a bit of RGB for the stars. It probably took me longer to process than to image! Still not completely happy with the result - but it is the best so far. Data from Roboscopes 12" F3.8 Newtonian using a 2600MM camera. All processed in PI.

Critical comment welcome.

Looks like we are in for cloudy days and nights now🙄.

🤣🤣🤣

Just to add to the comments above from @Stuart1971, I have run my Quieter2 from a 12v lead acid battery with variable voltage. I was a little concerned, but the second Mele PC I purchased actually had a sticker on it saying it required 12 - 19V.

32 minutes ago, Giles_B said:

Is there any formula that will give me my image size based on my aperture and focal ratio?

I guess you can use the filter size calculator. This does not have 0.6 reducer - but close enough. The 0.6 reducer has 38mm aperture which suggests it would be OK. The 75mm is a guess at the distance from the glass. I suspect you will get some vignetting, but for a 1600 sensor this suggests it would be OK. (I would take a punt - but don't take my word for it).

I have used my RC8 with ST80 guidescope on the HEQ5 and it just about managed - but due to the longer FL I decided it was not quite good enough. However, at the RASA FL it would probably be OK. Also, the RASA is lighter and you can use a small guidescope.

Normally I would say "try it and see", but obviously this won't help! The standard 0.8 reducer is designed for full frame use, so would think that the 0.6 should work on the 1600. I suspect if you are a pixel peeper, the stars might not be perfect - but it should be OK.

Might help...

Good advice above, but I would add that it is very dependent on your set up. I image with a 1600MM pro and a RisingCam IMX571 colour camera and I have no problem with a standard LED panel (tracing panel from Amazon) and very short exposures << 1sec. (Not recommended with a 294 sensor). This is particularly convenient when taking NB and LRGB flats at the same time as I do not need to alter the screen brightness. Similarly, with the RC8 I remove the dew shield for the flats and it is fine. Obviously, this may not be the case with an SCT due the effect of the corrector plate.

1 hour ago, dark knight said:

In particular I need a 5.5 x2.1mm centre positive  to usb c. This will connect the mounts hub to power a mini pc (USB c input). Anyone know where to get these, I can only find pd charging cables. Who would of thought the topic of cables would cause problems

I struggled to find these too. I ended up making mine with a standard 5.5x2.1 male to male then adding a 5.5x2.1 to USB C adaptor. However, I suspect the ones in the link from @TiffsAndAstro would be OK for low wattage.

I tend to go for shorter exposures on globular clusters - maybe 30 or 60s. I then try to remove any with poor star shapes to give the crispest image I can.

Nice image. Always worth adding a bit of Ha to this one.