Icesheet

5 hours ago, pete_l said:

While the CEM60 does look better on paper, can anybody actually point a finger at the images from that mount and say they are consistently any better than the same images (scope, camera, target) taken from an EQ6? Or that the imaging process s significantly easier?
Those are the factors I would investigate if comparing the mounts: the results, not the specs.

This is exactly what I’m getting at but as hard as it is to properly compare on paper due to the variables it will be just as hard to compare the results in final images due to the same factors. Unless someone does numerous side by side tests with exactly the same equipment. Perhaps beyond it all is what @ollypenrice and others have said previously, we’re probably going to be seeing limited anyway. FWIW, in my opinion, at shorter focal lengths (<1000mm) and a typical image scale of >1.5”/px I don’t think you’d notice the difference between the two mounts. Longer focal lengths and smaller image scale is where you might see the benefit from the CEM60 (on nights where seeing permits). 

3 hours ago, ollypenrice said:

The discussion in this thread turns to the subject of binning CMOS. 

Olly

Thanks! Interesting read.

Your rule of half seems to be consistent with what I’ve read and what the theory above suggests actually. I’ll be honest I hadn’t really thought about all this until I started considering this mount (and possible scope) upgrade. I’m glad I did though as I now feel I’m in a better position to chose a suitable set up based on my likely sky conditions.

Im curious to know why binning on CMOS sensors with small pixels would not be beneficial?

It sounds like the CEM60 is the one for you @cfrommen.  It's a shame you can't benefit from your NJP now. I couldn't find too much info on it but I'll send you a PM to find out more (in English, I'm a Brit in Norway!)

If I do go eventually go for the EQ6-R I will most certainly put the saved money to good use, thanks 

Thanks @cotak, and my reference to ‘god like’ guiding was based on your graph

I sold my HEQ5 so I need to find another mount now and may as well make it worthwhile that’s why I started looking at this. From reading around forums you commonly hear the CEM60 touted as a step up from the EQ6-R but that the EC version is not worth it. Based on the spec (and your experience) it seems to be the other way round. The CEM60EC is the real step up and there’s not much between the EQ6-R and the standard CEM60. 

I’m not chasing star FWHM, although like anyone else I would like them as tight as they can be. So instead of taking it for granted that the CEM60 would be the mount that gave me that, I wanted to try and confirm it. It now seems to me that I would not be giving up much by going for the EQ6-R over the CEM60. Aside of weight and cable management benefits which do not justify the extra cost for me. Again, all this being said without real world experience.

I guess my mind is made up about it really and I just wanted to hear if anyone could justify the extra cost of the CEM60 over EQ6-R, preferably through experience. Actually, I really thought about the CEM25EC given it may have been able to handle the payload but it only has latitude adjustment to 60deg and I’m slightly north of that. 

As to future upgrades I’ve learned to never say never with this hobby but I can’t imagine needing to load >20kg and I need a mount now. If I could stretch to the CEM60EC I would but I can’t and with the money saved the EQ6-R seems the better bet just now. No doubt I’ll curse the day I thought the weight and cable management were not worth it!!

I have looked into this is in a bit more detail. I didn't want to hijack @cfrommen's post with my input but if you would like to have a look and comment please do here.

Based on a previous post here: Help- CEM40, CEM60 or EQ6-R Pro, I decided to dig a little deeper as to how I could choose a suitable mount for my current set up (and potential future set up). If I had the money I would just buy a Mesu or CEM120EC and stop worrying that the mount may be my limiting factor. Unfortunately my pockets are only so deep and significantly emptier due to this hobby! A caveat to this post is that it is theoretical and not based on any real life personal experience. Also, all of the information has been sourced elsewhere so please correct any inconsistencies or errors I have made. 

Right now the most demanding equipment I have of a mount is an Esprit 100ED (550mm FL) coupled with an ASI1600mm (3.8μm)This set up weighs in at ~9kg and gives me an image scale of 1.43"/px. Therefore, regardless of anything else the resolution of my images will not exceed this threshold. Based on that my first instinct was as long as I have mount that can handle 9kg and guide with <1.43" Total RMS then my image quality would not be degraded by mount performance. As is always the case in this game it is not as simple as that. 

I stumbled upon a thread on CN about arcsec/pixel and guiding RMS in which a user explained that an approximation of your final output resolution can be determined by:

output resolution = sqrt(seeing^2 + sampling^2 + guidngRMS^2)

This is a simplification in itself and another user pointed out that there other inputs here, known and probably unknown. Have a read for more info. From my perspective this is a good enough approximation. Based on that equation my final output resolution will never be better than the largest input.

So if my seeing is 2", my sampling is 1.43" and my guiding is 1" my output resolution would be:

sqrt(2^2 + 1.43^2 + 1^2)

= 2.7"

That is the stars in my final image would measure 2.7"FWHM when ignoring any other factors.

Taking a look at this keeping the seeing and image scale the same but with examples of bad guiding (2"), good guiding (0.8") and god like guiding (0.3") you get the following outputs.

Bad = 3.2" FWHM

Good= 2.6" FWHM

God like= 2.5" FWHM

So by improving the guiding by the same factor sees diminishing returns in terms of final resolution output. Again, ignoring other factors.

If I know consider the image scale I would have based on the scope I think I would buy next, an Edge HD 8" it would look like this:

Edge with x0.7 reducer (1422mm FL) and ASI1600mm (3.8μm) gives an image scale of 0.55"/px (maybe I would want a new camera too!)

Using the same guide RMS for bad, good and god like (assuming I could achieve that at this FL) it would give the following:

Bad= 2.9" FWHM

Good= 2.2" FWHM

God Like= 2.1" FWHM

So while the unrounded numbers show a bit more disparity between Good and God like, the same diminishing return is apparent. Even at longer FL and higher resolution where I would have expected the difference in the improved guiding to really count. Only if I change the seeing to exceptional do you start to see a noticeable difference between good and god like guiding. Unless I'm not appreciating the difference 0.1" FWHM of stars has in resulting image quality? Perhaps the difference will be related to the amount of subs you have to throw out?

Now the two mounts I have been considering are the EQ6-R (£1179) and CEM60 (£1699) which if I include the price of tripod for the CEM60 likely takes it closer to £2000. It seems to me that the common perception is that the CEM60 is a significant step up to the EQ6-R. Based on the specs I can find online the peak PE of the mounts are, CEM60 <+\-5" (manufacturer spec) and EQ-R between +/-6-7" (no manufacturer spec but found some who had measured it online). Furthermore, based on the guiding experience I can find online there wouldn't be much that in it, certainly not the difference between good and god like I outlined here anyway. Perhaps iOptron are really conservative in their peak PE error and perhaps there will be a lot more variance in an EQ6-R so that I can be pretty sure of better consistency from the CEM60 but am I really going to see the benefit of that in my final images? I mean the difference between the mounts just now is a good chunk of the price of a brand new Edge HD 8"! 

I know much of this is a generalisation and perhaps I'm missing key aspects here? I know the CEM60 has higher resolution stepper motors, is lighter and has a higher rated payload (although, I note FLO recommend to consider 2/3 of quoted payload iOptron's products which would actually bring it line with the EQ6-R), but does it justify the extra cost? It seems I would have to move up to the CEM60EC to perhaps see the difference? 

I appreciate anyone's input here especially if you have experience with both mounts as real life experience is a better gauge than the potential the numbers might show. 

7 minutes ago, cfrommen said:

I am located just 20 km east of Oslo. I usually buy from Teleskop-Express in Germany or from whatever country with the best exchange rate compared to Norwegian kroner 🙂

After paying 25% import duties it doesn't make a huge difference though compared to buying from a Norwegian dealer. The problem is more that you cannot get certain things in Norway. Astrosweden and Teleskop-Express have the best deals on EQ6-R Pro (12.500 NOK) currently. The CEM60 w/o tripod is available for 15.600 NOK from Teleskop-Express right now. There is a waiting time of 4 weeks, however.

They're actually both cheaper at FLO, particularly the EQ6-R, it comes in at 10.600Kr on current exchange rates. I think the difference might be that FLO don't automatically display ex VAT prices until you get to the checkout whereas Teleskop Express do. After duties the EQ6-R comes in at ~14.000Kr. That's a saving of 3.500kr buying new here. Well worth it in opinion especially since it seems the dealers here seem to drop ship and don't hold stock.

Yeah, I was close to pulling the trigger on the CEM60 last month but was put off by the delays and now the price has increased £100  . I think I'm swaying towards the EQ6-R at the moment since it has the tripod and most people seem to guide <0.8"RMS. If money wasn't the object the CEM60 would be ordered already! This isn't helped by the fact I've added highend binoculars to my list of optics!

Good luck with it!

6 minutes ago, jjosefsen said:

Edit: I would add that I would trade my EQ6 Pro for a CEM60 any day of the week..

Would you pay double the price to do so though? Do you think that would justify the extra performance?

15 minutes ago, Rainer said:

I am iOptron biased 🤓

With that beast only a CEM 60. Moment arm not weight is here important. CEM 40 is too small for that even if it could carry it 40 lbs ~ 18kg ...

And if the budget allows it a CEM 60EC 🥰

Rainer

I didn't consider moment arm. So do you think the EQ6-R being physically bigger could handle his set up even although it takes the same payload?

I have exactly the same dilemma and I have a similar set up to you.

If you believe the EQ6-R will get the job done then the CEM40 will too. Your maximum payload of ~12kg is 2/3 of the rated payload of the EQ6-R and CEM40 which likely puts you towards the upper end of the mount capabilities for imaging. So if you are considering the CEM40 in my opinion given the price difference just now the CEM60 is a no brainer especially if you already have a pier. It will future proof you in the event you want to get something bigger (which let's face it will happen!).

For me the choice is really between the EQ6-R and CEM60 which is primarily a price over performance decision. Secondary to that is future proofing and portability. Since the CEM60 is going to work out double the price of the EQ6-R once I factor in a tripod  then the question is will I get the extra performance from the CEM60 with my 550mm focal length refractor to justify double the cost?I'm not sure there. Hopefully someone can answer that!

When it comes to weight I would rather carry a heavier mount out and have an extra £1000 in my pocket if I get say 80% of the performance in the focal range I'm imaging at. If I decide to get a longer FL instrument then it gets more difficult. My pockets are only so deep though!

P.S where in Norway are you and where do you usually buy from? It's almost always cheaper to import than buy from Norwegian dealers!

8 hours ago, MattJenko said:

Mine handles more than 8kg. SA, dovetail, counterbalance and the rig above is more than 8kg and it is solid in all manner of heights and configurations. Not sure about actual max though.

Thanks! Seems like a safe bet then and you cant really beat the portability. 

On 27/08/2018 at 08:53, MattJenko said:

I have the old version and the x0.79 reducer as well. I screw reducer directly into the end of the focuser and certainly don't use an extension, as the focuser is racked right in on the focuser as it is! If you are struggling, you could try inserting the reducer into the focuser as opposed to screwing in the end. This is less secure I found, but it means you can push it in further if it doesn't quite reach focus.

 

Hi Matt, 

I'm looking at getting this tripod for it's portability but I've read conflicting things about the payload capacity. Some sites say 8kg and some say 15kg (including Berlebach official site). What sort of total load do you have on it and have you experienced any problems with any of your setup's on it?

Thanks

Chris

Thank you! I just noticed that when I did this it seemed to turn the clock on the polar scope too. Was worried it was perhaps putting me off and limiting my exposure length.

I have a question for Star Adventurer users. After polar alignment can you release the clutch knob slightly and to help frame a target or by doing this do I compromise my polar alignment?

3 hours ago, Josh40996 said:

I use a Nikon D3200 for my images, I don't believe it is holding me back at the moment. I'd imagine you'd be best upgrading other equipment before the camera.

1 hour ago, M Astronomy said:

I would try and get better results with the equipment you have. Most DSLRs these days can get decent results with a standard lens and tripod. Keep trying! If you upgrade with the expectation of getting good results straight away, you will be disappointed. All the gear, and no idea as they say. Be patient, ask questions and most importantly get out there and have a go!

+1 to both of these!

I use a D3200 and I'm more than happy than the results I'm getting. 

5 hours ago, happy-kat said:

How heavy is that 500mm scope?

 

Ok, I've weighed everything. 

Scope- 2.3kg (2kg without rings)

Camera Body- 0.5kg

Orion Mini guider with GPCAM2- 0.75kg max

So total equipment weight would be 3.5kg max. 

Does the counterweight count towards the payload? If so ~4.5kg. 

Waiting on some parts so I'll see how I get. From reading it seems the focal length coupled with tracking error may be the limiting factor. 

5 hours ago, Thalestris24 said:

I think you might have to Still, nothing ventured...

Louise

Still, as you say Louise...

It's around 2.5kg with the finder scope and rings attached. Removing them would take it to around 2kg I guess.

1 hour ago, serbiadarksky said:

Well I had the chance to test out 400mm on the SA unguided, max exposure was 45sec, 50sec, 55sec with trails 

So I would say 50sec 400mm is max what you can get

Ok, so guided you might expect to get longer subs or maybe even similar exposures times with a longer FL? I have a 500mm scope which I'm keen to use. Seems like I'll be pushing it but there's no harm in trying I guess. Just worried if it doesn't work out it I might not necessarily be able to tell if it's down to my lack of experience or the limitation of the mount.

What is the maximum focal length people have had success with the SA, guided or unguided?

I see there is a 380mm example here. Anyone had success at 400mm+?

15 minutes ago, serbiadarksky said:

I'm glad to hear that you like it!

Iso: 200

Exposure time: 8-10 minutes each

Number of images: 60

Aperture: set at f3.5

I would love to know how you're getting 8-10 min exposures especially @300mm, that's amazing!

Are you autoguiding?

1 hour ago, Victor Boesen said:

I would get the regular star adventurer bundle.

+1 for this

Here's two of my better efforts so far. Was delighted that I was able to pull out the Horsehead from the Orion widefield. I have a lot to learn but I would not have caught the bug without the Star Adventurer!

All these done with a Nikon D3200 and Sigma 70-200mm F2.8. Exposures range from 60-120sec. Typically ISO800-1600 at f4-6.3. The lens really isn't the best but good enough just now.

I would not hestitate to recommend it to you!

Hi John,

Thanks for your reply, I will get an introductory post up soon

With regards to this scope, I'm going to try and get more info.... I've contacted the original vendor and if I can get it at a price that I feel comfortable losing if it all goes wrong I'll give it a go. It could turn out to be a great deal. I'm very intrigued after reading this post and some others on the scope.

I look forward to getting more involved in the forum

Chris 

Hi all, 

This is a strange first post but I'm bumping this up as I have the opportunity to buy an identical scope. I see Mr Julius hasn't posted for two years, did anyone know him personally that could ask him what his experiences with it were?

Here's some pics. I'm actually a beginner. Would something like this be putting me in way over my head?

Cheers

Chris