Is the advice "The HEQ5 is the entry point to AP" just plain wrong?

[Lotinsh]

Well since you've guys mentioned the thread I've created, I bought the EQ5 at the end of the day and got a single motor drive, so far I haven't used it too much, as it's literally been cloudy everyday since fall. But one image I was able to capture (single exposure of Orion) looked amazing, I am still proud of it, even though it is out of focus since I seem to have a difficult time with collimation (maybe I'm just a moron) of my 130p Heritage, I don't have any tools for that, so there's that, I couldn't reach focus that night quick enough before clouds came. But overall my experience seems to be good so far, well at least for now my main focus is understanding how to do all the other things before worrying that much about the mount, my priorities are ,collimation and overall I'm trying to understand what in the world I'm doing, etc. I'm thinking of buying a new telescope for astrophotography, since the 130p Heritage isn't meant for it, which I didn't know before. So there's that.

I'm not sure if I should've posted this in the other thread, but since the thread has been mentioned here I'm posting it here, sorry if this is the wrong place.

Edited January 31, 2022 by Lotinsh

[happy-kat]

Have a look at the No EQ DSO Challenge thread @Lotinsh there is an active contributor who is using the heritage 130p telescope and has shared their approach to nailing focus.

[FLO]

On 29/01/2022 at 12:49, vlaiv said:

I have to correct myself - EXOS2 can't take 13Kg photographic payload (18Kg visual) - that seems to be error on @FLO's website. On TS website both EXOS 2 mounts (Bresser and ES one) are listed at 13Kg max payload

For the Explore Scientific EXOS-2 mount we say '12.7kg imaging / 18kg visual'. This specification is provided by the manufacturer so should be correct ...

Manufacturers often exaggerate mount payloads so if we hear from owners the specification should be reduced then we will happily do this (we have already done this for most Sky-Watcher mounts at our website). 

HTH, 

Steve 

[ollypenrice]

14 hours ago, wuthton said:

Same for me!

@ollypenrice Let me give you a budget restraint,  the Samy, DSLR and the HEQ5... or Samy, AZ-GTI /EQ3 pro and a dedicated, cooled camera, with which could you take the most impressive image? I know my answer.

I'd probably go for the cooled CMOS camera because I've never really been a fan of the DSLR for AP. However, the EQ3 choice would not offer future proofing much beyond the Samyang in my view.

I've asked a few times on this thread about what EQ3 owners achieve in RMS under guiding.  Anybody?

Olly

[vlaiv]

1 hour ago, FLO said:

For the Explore Scientific EXOS-2 mount we say '12.7kg imaging / 18kg visual'. This specification is provided by the manufacturer so should be correct ...

Manufacturers often exaggerate mount payloads so if we hear from owners the specification should be reduced then we will happily do this (we have already done this for most Sky-Watcher mounts at our website). 

HTH, 

Steve 

Bresser website lists that same mount at 13Kg max payload ...

https://www.bresser.de/en/Astronomy/Accessories/Mounts/EXPLORE-SCIENTIFIC-EXOS-2-PMC-Eight-GOTO-Mount.html

[FLO]

2 hours ago, FLO said:

For the Explore Scientific EXOS-2 mount we say '12.7kg imaging / 18kg visual'. This specification is provided by the manufacturer so should be correct ...

Manufacturers often exaggerate mount payloads so if we hear from owners the specification should be reduced then we will happily do this (we have already done this for most Sky-Watcher mounts at our website). 

 

1 hour ago, vlaiv said:

Bresser website lists that same mount at 13Kg max payload ...

Bresser is a distributer. 

I think you are saying for the Explore Scientific EXOS-2 mount we should delete the specification provided by Explore Scientific and use instead the specification provided by the German distributor and German retailer. But neither say if their 13kg specification (same as Explorer Scientific' specification for imaging) is for imaging or visual and we do not believe German retailers have access to more information than UK ones.

My colleague Chris used an EXOS-2 mount for imaging with an 8" Newtonian. His experience suggests 10kg for imaging (his scope/camera/etc weighed 9kg) and 15kg for visual is about right, so we will edit our page to show that. 

HTH, 

Steve 

[wuthton]

2 hours ago, ollypenrice said:

I'd probably go for the cooled CMOS camera because I've never really been a fan of the DSLR for AP. However, the EQ3 choice would not offer future proofing much beyond the Samyang in my view.

I've asked a few times on this thread about what EQ3 owners achieve in RMS under guiding.  Anybody?

Olly

For me, the entry point to "serious" astrophotography is not the HEQ5 it's a cooled camera which need not be expensive, you can pick up the baby Atik 314 for £200 and the (imo) sweet spot for high return astrophotography is 85-500mm of focal length, do I really need a HEQ5 at those pixel scales? 500mm with an Atik 314/383, you can use an EQ5 Pro easily. At 250mm you'll not see much difference without pixel peeping between my AZ-GTi (rms +/- 2, I assume an EQ3 would be a bit better) and a HEQ5. I haven't used a CMOS camera but from what I've read they cement my opinion.

I've got one last question for you and then I'll leave you in peace. Over the years, approx what percentage of your imaging time has been spent at over a metre FL? Me less than 10%.

Edited February 1, 2022 by wuthton

[ollypenrice]

3 hours ago, wuthton said:

For me, the entry point to "serious" astrophotography is not the HEQ5 it's a cooled camera which need not be expensive, you can pick up the baby Atik 314 for £200 and the (imo) sweet spot for high return astrophotography is 85-500mm of focal length, do I really need a HEQ5 at those pixel scales? 500mm with an Atik 314/383, you can use an EQ5 Pro easily. At 250mm you'll not see much difference without pixel peeping between my AZ-GTi (rms +/- 2, I assume an EQ3 would be a bit better) and a HEQ5. I haven't used a CMOS camera but from what I've read they cement my opinion.

I've got one last question for you and then I'll leave you in peace. Over the years, approx what percentage of your imaging time has been spent at over a metre FL? Me less than 10%.

I've done a great deal of imaging at over a metre. Six years or so with a 14 inch ODK but, more recently and with small pixel cameras, I've done similar targets with a metre of FL and a TEC140. On balance I prefer the TEC but the 14 inch would have been more productive had our camera been willing to work binned 2x2. Unfortunately it refused to so so. Sometimes they won't. I do wonder if the more-than-a-metre FL has had its day unless you have a site of exceptional seeing.

Olly

Edited February 1, 2022 by ollypenrice
typo

[vlaiv]

5 minutes ago, ollypenrice said:

I do wonder if the more-than-a-metre FL has had its day unless you have a site of exceptional seeing.

It will always be faster setup than a small scope for certain targets.

[wuthton]

45 minutes ago, ollypenrice said:

I've done a great deal of imaging at over a metre. Six years or so with a 14 inch ODK but, more recently and with small pixel cameras, I've done similar targets with a metre of FL and a TEC140. On balance I prefer the TEC but the 14 inch would have been more productive had our camera been willing to work binned 2x2. Unfortunately it refused to so so. Sometimes they won't. I do wonder if the more-than-a-metre FL has had its day unless you have a site of exceptional seeing.

Olly

I've no doubt that you've done a lot over a metre but I've got a sneaking suspicion that as a percentage it's in the minority.

Astrophotography doctrine has always been "work from the mount up" but I've thought for a few years now that a better mantra would be "short focal length and a large pixel scale is your friend" for the following reasons.

- Cooled, large pixel cameras are getting cheaper and more obtainable as each year passes.

- Software improvements, particularly backlash compensation can make a mediocre mount guide like a dream.

- The cost of good quality, short and fast optics has dropped through the floor.

[vlaiv]

5 minutes ago, wuthton said:

I've no doubt that you've done a lot over a metre but I've got a sneaking suspicion that as a percentage it's in the minority.

Astrophotography doctrine has always been "work from the mount up" but I've thought for a few years now that a better mantra would be "short focal length and a large pixel scale is your friend" for the following reasons.

- Cooled, large pixel cameras are getting cheaper and more obtainable as each year passes.

- Software improvements, particularly backlash compensation can make a mediocre mount guide like a dream.

- The cost of good quality, short and fast optics has dropped through the floor.

I'll disagree on all three counts.

All modern cameras have small pixels. Cheap large pixel camera available second hand is anecdotal event rather than regular thing.

There is no software that will make mediocre mount guide like a dream - otherwise we would all be using it.

Would like to see good (astronomical) quality short and fast optics at affordable prices

[Alien 13]

22 hours ago, wuthton said:

Same for me!

@ollypenrice Let me give you a budget restraint,  the Samy, DSLR and the HEQ5... or Samy, AZ-GTI /EQ3 pro and a dedicated, cooled camera, with which could you take the most impressive image? I know my answer.

Can I have a go...Give me the Sammy, DSLR and AZ-GTI/EQ3 with single axis motor 😃 Cant be doing with anything that is not self powered or involves a laptop to capture images.

Alan

Edited February 1, 2022 by Alien 13

[ollypenrice]

16 minutes ago, wuthton said:

 

Astrophotography doctrine has always been "work from the mount up" but I've thought for a few years now that a better mantra would be "short focal length and a large pixel scale is your friend" for the following reasons.

 

Surely you're preaching to the choir, here, though?  Precisely this advice is given almost as often to beginners as the advice to regard the HEQ5 as a minimum. I've no idea how many dozens of times I've said it myself over the last decade or more.

Yes, I've been more a widefield junkie than a galaxy or PN specialist over the years and have made or collaborated in a number of 30+ panel mega-mosaics, but I wouldn't be without the high res stuff I've done as well.

https://www.astrobin.com/347486/B/

https://www.astrobin.com/full/393219/0/

Another thing I've enjoyed is adding high res data to widefields for the 'areas of interest.'

https://www.astrobin.com/full/335042/0/

I would never advise anyone to start with high res, though, because it is less forgiving, much more expensive and needs stable seeing as well as transparency.

Anyway, when are we going to hear chapter and verse on the guiding RMS of the EQ3 Pro? It's time for an infusion of facts into this conversation!! 😁 I've no idea what this mount can deliver since I don't even recall seeing one in the flesh, but if it's good enough to run at half the pixel scale of its imaging rig (or thereabouts) I'll gladly doff my hat to it.

Olly

[newbie alert]

47 minutes ago, wuthton said:

Cooled, large pixel cameras are getting cheaper and more obtainable as each year passes.

Large pixel camera's? Pixels have been getting smaller.. I do hope that they revert to getting bigger but as the  cmos market dictates what sensors are available they can only use what's being produced... most camera's that are being used are under 4um...that's not big

[tomato]

I must agree with  @vlaiv on at least one point, no amount of clever software will compensate for an under engineered mount, especially one carrying it's maximum payload. I think someone of Scottish ancestry said "you canna change the laws of Physics"?

 I had a quick look at some threads discussing entry level mounts for AP and my general conclusion is that the SGL community having given reasonably well balanced advice. Almost all of the "HEQ5 is the minimum mount you should get posts" have qualified the statements with why the  choice of target, the  combination of equipment or expectation of the results obtained,  would require the mount, and the threads are sprinkled with numerous posts extolling the virtues of the EQ3 mount or similar, but again highlighting it's limitations, the additional work involved in optimising it's performance and what kind of AP it is best suited for.

I think with the diverse membership of a forum like SGL covering the full range of experience, knowledge and budget, you are bound to get a wide range of opinions but I don't think any of those expressed have been deliberately dismissive of folks wanting to try out AP on a limited budget. 

Quite a few mention buying the "Making Every Photon Count" book, still the best piece of advice IMHO for anyone starting out on AP. I have just read through the choice of mount section and although inevitably the technology has moved on a bit, it's still sound advice in my view.

[vlaiv]

29 minutes ago, ollypenrice said:

Anyway, when are we going to hear chapter and verse on the guiding RMS of the EQ3 Pro? It's time for an infusion of facts into this conversation!! 😁 I've no idea what this mount can deliver since I don't even recall seeing one in the flesh, but if it's good enough to run at half the pixel scale of its imaging rig (or thereabouts) I'll gladly doff my hat to it.

I did a brief search and reported figures vary greatly although there is not much data to go by.

I've seen below 1" RMS reported and over 3" RMS reported.

I'm sort of skeptical of 1" RMS performance from EQ3 class mount given that it even does not have proper ball bearings on DEC shaft. Motor resolution is about 0.28" / step as well - so that is somewhat limiting. Next problem is 480s period - which is rather quick. That leaves 240s for P2P and if periodic error is worse than say Heq5 (being 30-35") - maybe say 45" then we will have 0.1875"/s on average. It takes only few seconds for mount to drift 0.5" - and sometimes even faster than that (periodic drift is never uniform).

My vote goes for 1.5-2" RMS on average when tracking near meridian.

[ONIKKINEN]

14 minutes ago, newbie alert said:

Large pixel camera's? Pixels have been getting smaller.. I do hope that they revert to getting bigger but as the  cmos market dictates what sensors are available they can only use what's being produced... most camera's that are being used are under 4um...that's not big

Smart phone cameras have pixels as small or smaller than 1 micron, so i think its safe to say the general trend of pixels getting smaller will continue, since daytime/normal photography needs and wants are what sensor manufacturers will focus most on. If read noise and other camera noise sources continue improving along pixel sizes i could imagine a 1 or 2 micron pixel camera to be quite convenient. You could BIN the camera to work at any resolution you want with a wide variety of scopes were this the case.

44 minutes ago, ollypenrice said:

Anyway, when are we going to hear chapter and verse on the guiding RMS of the EQ3 Pro? It's time for an infusion of facts into this conversation!! 😁 I've no idea what this mount can deliver since I don't even recall seeing one in the flesh, but if it's good enough to run at half the pixel scale of its imaging rig (or thereabouts) I'll gladly doff my hat to it.

Olly

PHD2_GuideLog_2021-09-02_005223.txt

Since there are no others interested in sharing theirs, ill share mine. Note that this is not from the EQ3-2 but the EQM-35PRO which has a slightly improved RA axis (but the same DEC axis) and a steel tripod.

I dont remember exactly what happened during this session but it was one of the last times i shot towards low declinations (this was M33 at dec 30). Payload was within advertised limits, so around 8.5kg/10kg. For what its worth FLO seems to have a more reasonable estimate of 7kg in imaging payload for the mount, although i would be wary of suggesting someone mount a 7kg imaging setup on this thing.

I bet you've never seen periodic error in DECLINATION 😎. Well not really periodic error, but if you inspect the log you see it goes off on a trip somewhere after every dither in RA or any other anomaly in RA guiding.

Total RMS of 1.37'' in RA and over 3'' in DEC, but short exposures can be used since DEC does whatever it wants anyway and wanders off occasionally. Unguided is not a wise choice since the P2P error in this case was 45''. So while its not good, it looks like a very wide 6 arcsec/pixel setup would not care about the hiccups. And the hiccups would probably not be as bad and declination would also be usable, so i do think it can work for very low resolution imaging just fine. But thats not really the point, the point is this thing is just a waste of money for someone who wants future proofing.

[malc-c]

Don't have the actual log file, but I sent this screen grab to a friend as I was pleased with the sub 1 acr sec RMS guiding I was getting the first night of using the 9 x 50 finder / QHY5 set up as a guidescope

But I confess I have no idea if these figures are meaningless.  From what I gather PHD2  calculates that based on the pixel scale, which for me with a 181mm focal length and a 5.2um pixel size was I believe 6 (someone will no doubt correct me ).  So can you compare these RMS figures with say someone using a longer guide scope with a different camera??

Bottom line is that the images I took when guiding resulted in pin point sharp stars and as good a detail as I would get form a LP town location. 

Thing is I feel this thread has gone off the rails somewhat.  Rather than discussing the pros and cons of the HEQ5 and why it is or is not the ideal mount for imaging, we're now discussing pixel size and is heading towards a [removed word] contest with people passionate with their views of what equipment should take priority when setting up a rig.

Part of the problem is that unless we have some luck and win the lotto none of us can purchase 10 or so mounts and compare them under the same circumstances, so whilst we have opinions of why a mount on paper shouldn't be or isn't ideal, in practice people are getting some results. The effort in to getting those results is subjective to the individual.   Some will want to get the images they see in magazines right out of the box with no effort, others are quite happy to spend hours balancing the rig to get the best performance as the rig is on the limit for the mount.  There's a long running thread on using the EQ3 as an imaging platform, so some are managing to get it to work.  Equally as it has been mentioned, look at the DSO section and most of those images are taken with gear on an HEQ5 or equivalent, or higher spec mount, so there is some reasoning to suggest that you do need to invest at this level.

As I said before, we will have to respect each others viewpoints and maybe move on... 

 

[ollypenrice]

8 hours ago, malc-c said:

 

Thing is I feel this thread has gone off the rails somewhat.  Rather than discussing the pros and cons of the HEQ5 and why it is or is not the ideal mount for imaging, we're now discussing pixel size and is heading towards a [removed word] contest with people passionate with their views of what equipment should take priority when setting up a rig.

The title of the thread was, Is the advice "The HEQ5 is the entry point to AP" just plain wrong?  Quite honestly I can't recall many threads which have remained as firmly  on topic as this one!  You cannot have a rational and objective discussion about any mount without including pixel size. A setup's resolution is determined by just two numbers, one of which is pixel size and the other focal length. A mount's fitness for purpose is defined by it's ability to support this resolution. That is precisely the point of the discussion, which is why I think it has remained on topic. As for what should take priority when setting up a rig, I'd have thought this was also implicit in the original post?

I hope you don't find anything acrimonious in anything I've said along the way.  No acrimony has ever been felt or intended.  If the latest EQ3 is an alternative proposition to the oft-cited HEQ5 then that's great news and those with experience of the mount are free to express their satisfaction. Your figure of 1.02 arcsecs is very persuasive evidence in the mount's favour. (We're having a bit of a fight with our Avalon Linear at the moment and for some reason that's about where we are with it. It should be better but isn't, or not consistently.)

Olly

[wuthton]

13 hours ago, vlaiv said:

I'll disagree on all three counts.

All modern cameras have small pixels. Cheap large pixel camera available second hand is anecdotal event rather than regular thing.

https://astrobuysell.com/uk/propview.php?view=181603

There is no software that will make mediocre mount guide like a dream - otherwise we would all be using it.

I'll confess to being a bit overzealous with the language but I did quote my rms to +/- 2 with the AZ-GTI which I think is fair, I've seen it close to 1 but to then claim it's a rms 1 mount would be disingenuous. Never the less guiding software used to be a fairly blunt tool, it seemed like black magic at the time.

Would like to see good (astronomical) quality short and fast optics at affordable prices

You can pick up a good, brand new F6 refractor for the same money, not adjusted for inflation as what SW ED80, F 7.5 cost 15 years ago.

 

[newbie alert]

19 minutes ago, wuthton said:

Blah blah blah 

The 314 isn't a modern cam, it's not even made anymore, it's sensor ( 825) isn't produced anymore.. it was superseded by the 4 series 414 which isn't made anymore ( I'm not knocking them, they're amazing camera's) but they can't be put into the modern camera bracket,what's the 314, 10-15 years old at a guess?? Which is precisely what Vlaiv was saying

Can't see where you're going with the refractor comment 

[wuthton]

I think the Skywatcher ED80 is an excellent example of what I've been clumsily trying to say.

We give advice on this forum from our past experience which is largely made up from good advice that we've received in the past. The Skywatcher ED80 was recommended as an AP refractor for beginners, long, long, long after it should have been put out to pasture. It was recommended by people who'd been recommended it, used it, and had good results, it was advice given with good intention but times had moved on.

I think we just need to occasionally ask ourselves, is the good advice I received still good advice today. 

[newbie alert]

10 hours ago, malc-c said:

Don't have the actual log file, but I sent this screen grab to a friend as I was pleased with the sub 1 acr sec RMS guiding I was getting the first night of using the 9 x 50 finder / QHY5 set up as a guidescope

As I said before, we will have to respect each others viewpoints and maybe move on... 

 

Malc, I respect your honesty as most that spout their rms figures talk in pixels and not arc secs per pixel, a arc sec is precisely that a pixel can be anything as the camera and guidescope could be anything 

Another thing often missed is the peak to peak error, on your graph the DEC and RA RMS aren't that drastic, but the peak to peak are

As Olly has suggested many times round stars aren't necessarily a sign of good guiding,  small round stars are..stars are points of light, not blobs

In your post above the pixel scale of the camera and guidescope is 5.93 arc secs per pixel ( says it in the box) 

You need to guide under your image scale( some work on 1/2 image scale) but I think as long as it under it's fine

Sky limitations are also a major factor, you can't image under your seeing conditions no matter how well you guide

 

 

[newbie alert]

1 hour ago, wuthton said:

I think the Skywatcher ED80 is an excellent example of what I've been clumsily trying to say.

We give advice on this forum from our past experience which is largely made up from good advice that we've received in the past. The Skywatcher ED80 was recommended as an AP refractor for beginners, long, long, long after it should have been put out to pasture. It was recommended by people who'd been recommended it, used it, and had good results, it was advice given with good intention but times had moved on.

I think we just need to occasionally ask ourselves, is the good advice I received still good advice today. 

Id say so yes,  are you trying to say it isnt then?

The skywatcher 80ed is a awesome scope, punches  way above it's price tag.. as it happens I used one with a 825 sensor and I'd happily use both again .. I only got rid of it as I thought I was getting a better scope with my ZS80.. anyhow I am going way off topic here

Back on topic, I agree with Olly.. if you can't hold the sensor on target for the duration of the exposure you won't get the pretty pics that we're all looking for.. there's different levels of pretty pics, look at Ollys... he has a high level of experience and it shows within his images 

Edited February 2, 2022 by newbie alert
Added info

[malc-c]

6 hours ago, ollypenrice said:

The title of the thread was, Is the advice "The HEQ5 is the entry point to AP" just plain wrong?  Quite honestly I can't recall many threads which have remained as firmly  on topic as this one!  You cannot have a rational and objective discussion about any mount without including pixel size. A setup's resolution is determined by just two numbers, one of which is pixel size and the other focal length. A mount's fitness for purpose is defined by it's ability to support this resolution. That is precisely the point of the discussion, which is why I think it has remained on topic. As for what should take priority when setting up a rig, I'd have thought this was also implicit in the original post?

Olly, that's a fair comment, but also highlights that you can't just take the mount as singularity, the whole rig has to be looked along with the individuals expectations.  Throughout the thread its been mentioned that a decent camera is more suited, but then bolt that ideal camera to a scope with poor optics and you're back to square one with disappointing results, same could be said for vice-versa, but I'm in the opinion that a decent set of optics will give a better result with a less than ideal camera than the other way around.   

It may well be that something like an a £580  ED80 with a cooled camera such as the 314L that was mentioned above (currently around £1100) would do very nicely on a £200 EQ3 with a £140 dual motor drive.  But at circa £2k that is way above what we see in a lot of the "I want to get into AP - I have £300" type post.  If you compare the price of the EQ3 pro goto at circa £480 and the HEQ5 at £949, I think it's worth throwing that additional £470is at the mount and getting the HEQ5, especially if you have a grand to spend on a cooled camera. - But that's my opinion.  Not based on fact, just on preference if I was shelling out two and a half grand on an "serious" (there's that word again) imaging rig