Catanonia

Normally you see rasa images of widefield nebula and dust. Not so often on star clusters.

So I decided to have a go to see what would happen as I expected the stars to be "mis-shaped" due to the cables running over the corrector plate as the camera is on the front.

I am using a semi circle 3D printed cable router to try and reduce this

Here is the image and if you zoom in, you can see the misformed stars on the larger ones.

Overall, for a widefield in 60mins  (60x 1min subs at bin x1) not too shabby as long as you don't zoom in too much.

One of the downsides to the rasa.

A cracking and very natural coloured image. I prefer them this way.

Are you using a flattener / reducer and if so is your ccd distance correct as you have mis formed stars in the corners ?

This a terrible target from LP regions. 

I have been trying this for years and want to try it now with my rasa, but not had a chance.

This image, so much better than my previous attempts and love the FOV.

You can tell the noise is being controlled with the resolution and seeing, but a great image and if I could get close to that, I would be happy.

ASI 2600 MC Pro, Bortle 6 skies and about 2 hours in 2min 1xbin subs.

Don't think I can pull much more out of this, so here it is

1 hour ago, StarryEyed said:

I've lived in London all fifty five years of my life and astronomy been a blast. Theres plenty of things you can do other than snap snap snap. Do some variable, astrometrics work be a bit more of a scientist and less of a tourist its more demanding and can be more rewarding. eclipsing and exposive binaries will impress you for sure then up to exoplanet hunting. Cant see anything from the city is just wrong you can experience the full monstrous might of the universe if your up for the challenge. 

Wise words

28 minutes ago, Sp@ce_d said:

I was looking at that too.. I thought long & hard when FLO brought them out, as I love my 8"RC carbon but don't love the collimation .. ended up with the 150 frac. Did you get the shroud too?.. I'd be looking at an OAG rather than a separate guide scope though?.. yeah the EQ8 should be fine.

I have an battered ED80 and WO66 to try as guide scopes and so will try that 1st before the OAG route.

Didn't get a shroud, but can always pick one up later if I need one.

Collimation is a concern, but have plenty of experience on F2.8 Newts and also got that new video collimation camera / software to go along side the Cheshire and other collimation kit I have.

I have been toying with the idea of selling the RASA8 and getting a RASA 11 because of the issue of switching out filters. The 11 gives you nearly 3x back focus to put in filter sliders etc with a ZWO 2600

But I would then have to get a full frame camera to suit the scope and really only have a bigger RASA with a little less FOV for a shed load of cash.

Sooooooooooo

@FLO only had this little beauty up for sale  

This gives me a long Focal Length scope that I don't own for galaxies that I used to love imaging.

Added a 0.67 reducer into it and a few other extras and saved myself a pretty packet in the long run.

Keep the RASA8 for fast widefield 400mm F2 imaging and have the RC 10 for F8 2000mm or F5.3 @ 1340mm and all using my ZWO 2600

I have 2 smaller old refractors I can pick to use as guide scopes and the EQ8-R should handle that no problem

Happy bunny and thanks to Chris @FLO for answering my questions out of hours when he should have been home

Clouds for the next 6 months, sorry

@vlaiv Many thanks, most useful and some topics for me to research.

Tough one.

Many people image and post from cities using the lExtreme type of filters with excellent results for the circumstances.

Now don't get me wrong or take this the wrong way, such imagers seem to post images saying "it is possible", but it is clear that the images are no way as good as they would be from a Bortle 4 site.

It WILL be a huge disappointment to you compared to the Bortle 4 you are used to.

Cooled astrocam will do nothing compared to dslr (in grand scheme of things) as light pollution is the problem here for OSC

Mono Narrowband imaging would be my preferred method, but that means moving away from your OSC

So it really comes down to 

• Are you that into the hobby that you will accept anything rather than nothing and move on ?
• Moving to a city WILL reduce your imaging quality massively and you can only plaster over it with filters and other techniques for OSC unless you go mono narrowband

A tough decision

I have a RASA 8 on a EQ8-R which is great for F2 widefield paired with a ZWO 2600MC Pro.

It has its downsides with changing filters due to back focus and have been contemplating swapping it for a RASA 11. This is £4600 or more upgrade (yes will get some back on sale of the RASA8)

On top of that I would really need to upgrade to a full frame camera from the APC 2600 to get the full benefit from the 11, another 4k or more !!!!

What would I get from it all, the same really with the ability to change filters easier, but the same as the 8 nearly.

Well I don't have a long focal scope and so galaxy season is really out of the question for the Rasa

This has got me thinking, how about one of these below from FLO, keep the Rasa8 and have this as well for a fraction of the upgrade costs ???

I have never used one of these scopes before, I understand some of the principle, but have some questions to those in the know if you would be so kind.

• What are they like to collimate ?
• Do they produce flat fields, or is a corrector needed ?
• What drawbacks do they have ?

11 hours ago, gorann said:

You and me talked about it Cat. I can see the filter issue. But you really need a full frame APS sensor to make it worth while, or you only get half the FOV (and no more fotons collected). And then you need a big mount to carry the very heavy RASA 11. My Mesu200 would have no problem with that but I still went for a dual-RASA8 rig rather than a RASA11 (same light grasp). Maybe I rethink it one day, but a RASA11 with and APS-C sensor does not make much sense to me since I am after the big FOV.

Yes, a new camera would be in order to get the full benefit. This would be the next step when money allows. Rasa 11 and then a full frame.

I have an EQ8-r so mount not a problem

2 hours ago, ollypenrice said:

I wouldn't regard the 8 to 11 as an upgrade so much as a change.  It works both ways: the 8 gives a wider FOV. On the other hand the 11, I think, will cover a full frame chip, restoring a lot of FOV. Call it an upgrade if you also change the camera...

Olly

Yes you are correct. The main reason is the larger backfocus with the 11 compared to the 8 for me as it is a real PITA having to take the camera off to remove / add filters.  That and "bragging rights"

21 hours ago, ollypenrice said:

Yes indeed, very modest exposure time. But if we compare the RASA 8 with an 80mm refractor, which might be the alternative at this kind of FL, the RASA has (allowing for the central obstruction) 4.9x the light grasp. So 3 hours equates to 14.7 hours. Six panels later, that comes to an alarming 88 hours, as opposed to 18. On the other hand the stellar image quality, seen at full resolution, is not as good in the RASA as from a good refractor. But then, on the other other hand, the fast F ratio is stunningly good on separating nuances in the dust.

I'm really enjoying the RASA. It's brought a fresh approach to imaging for me.

Olly

Why I love mine so much and wanting to upgrade to a Rasa11 so I can add a filter drawer with the extra back focus the bigger Rasa has over the 8 when using a 2600

Nice work buddy, the EQ8 is a great mount.

Got mine all sorted now for power etc etc and really happy with it.

Delete everything other than the following

• Light Data
• Master Dark, Master Bias, Master Flat
• Final Image

Everything else can be created from them and no need to archive them.

I have just tidied up my storage and reduced it from 2tb to 1tb. It does start to mount up if you don't keep on top of it especially if you have a large megapixel camera.

On 29/01/2022 at 04:51, MKHACHFE said:

Excellent work mate. Gorgeous image 👍

 

Cheers

Thanks buddy

The scope is always removed after every session and stored in a nice dry garage in it own box to prevent fungus etc etc

The mount is then dried down and the cover is opened up every 2 or so days to allow it to breath, so far no issues experienced.

The cover has air that circulates around the bottom as it is not completely air tight, but I will keep an eye on it.

Not sure what will happen in summer with hot temperatures.

Wanting to keep a mount permanently outside and as safe from the elements as possible ?

Now I have my EQ8-R and I will always keep it outside on the patio, so I wanted to protect it as best as possible from the elements.

Stargazer telescope covers can cost £170, but this from Amazon is perfect - 

https://www.amazon.co.uk/gp/product/B09J2H2118/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

I got the bigger version and it easily fits over my EQ8-R and RASA8 with room to spare. I place the edges under the flat feet of the tripod so the whole mount is totally enclosed on my patio. 

Even has a zip down the side, so unzip, remove over the side of the mount without unhooking it from tripod feet and zip up again when done.

Well worth the £23 

15 minutes ago, vlaiv said:

It can be more than that - it can be valuable resource as is envisioned - it just needs few corrections and different interpretations of results.

For someone that wants easy advice to match two pieces of equipment - like scope and camera - it can do wonders.

Imagine you come and say - I want this scope and that camera, is it good combination?

And it says - yes, it is good combination given average seeing but only if you bin your data in such and such way and you have mount that is capable of such and such performance.

I'd add couple more things like illuminated and corrected field versus sensor size.

I'm sure that most people with experience do this "manually" when choosing potential combination - why not offer it as a tool that does the same view few clicks

Vlaiv,

No doubting your expertise in this subject and I would not even try to dispute any of it.

BUT

is there a danger that if your recommendations are applied to the site, it becomes "too" complicated for the newbie / average human and therefore effectively worthless ?

The site is supposed to be a top level guide for those that don't understand the science as you may understand it 

All I would say, is reading the original descriptions on the site, it makes sense to my small brain but reading your descriptions hurt my head.

I would only say, what ever is decided upon, dumb it down to simple language for us simpler folk

Managed to get first light on the EQ8-R last night for an hour and it was fantastic to use.

Polar alignment was a doddle and the best I have ever achieved with ASI Air Pro. The RA and Dec movements were butter smooth even with the scope all mounted up.

Tracking was great too, the best I have had for a very long time and even in windy conditions

Well worth the investment, this mount is a beast, weighs a tonne and does not move one nanometre

11 hours ago, jacko61 said:

Just to clarify, I had both the hub power and  mount power plugged in and switched on. The camera wouldn't register till I plugged the camera cooler in to the mount power sockets. 

AH that is different and strange. No idea what happened there unless the hub needed power to run basic USB tasks and make the camera visible or activate the actual USB hub. Not tried this myself as all my kit is plugged into the ASI

9 minutes ago, cajen2 said:

'kin'ell! Not exactly grab and go! 😄

Nope, the tripod is a good lift on it's own.

If you are fairly fit, then you could do it

4 hours ago, jacko61 said:

Knowing how big the mount is, the tripod must be huge!!.  Good luck with it. I've been checking out the cabling hub this lunchtime and found that my ZWO ASI533 isn't recognised through the USB 3 hub in the mount unless I plug the 12 volt power in for the camera's cooler. Just having the 12v aux power in the mount doesn't 'do it' although everything else (polemaster, focusser and guidecam) worked fine.  

graeme.

This is because the USB hub is unpowered without the 12v external power attached and the camera doesn't get it's power.

Makes sense if you think about it.

This means that the power and USB hub is totally separate to the actual mount and its power.

This I did not expect and is a little bit disappointing as I still have to run cables that can snag to moving parts.

2 minutes ago, StevieDvd said:

The problem with 'some' of the newer SW mounts with onboard usb port is that the driver needed is different on some production models. Not such a problem on Windows as the  driver is easy to update. On Linux the driver is part of the kernel and an rpi-update command can resolve this. So a user with a self installed Linux where they have access to the command line can do this, but the ASIair is restricted.

Either use a reliable eqmod cable, download the image file for the ZWO modded OS or if you are a techie add ssh to the ASIair as per Github instructions and update the kernel.

I used the new "special" firmware and working perfectly now.

Thanks

16 minutes ago, Tomatobro said:

I removed my EQ6-r off the pier and put the EQ8-r on and connected it up the NUC using the same FTDI cable I used on the 6r. EQmod worked without any issues in that it did not know that the mount had changed.  I would guess that the ASIair would not know that the mount is a 6r or 8r based on that so reading the link you attached it should work ok.

SkyWatcher changed the USB / Serial hardware in the middle of last year and the ZWO ASI Air Pro base OS does not have the correct drivers. Using the image I posted sorted this out