StellarDrive HEQ5 or iOptron GEM45-EC

[KP82]

I've had my HEQ5 Pro for about 18 months now. I installed the rowan belt kit myself 3 months after I bought it. I also did a bit of re-grease at that time. The mount has been working fine with my WO Megrez 90 (now sold) and APM 107. My average RMS error with guiding is between 1.8 and 2.0 arcsecs with the imaging equipment in my sig. However since acquiring my APM 115, the increased weight has made the RMS figure worse (The PHD2 graph is more jagged). Looking at the specs I'm afraid my setup is close or possibly has exceeded the recommended imaging payload capacity of the HEQ5. So I'd like to get some upgrades for my mount. I found this StellarDrive (hyper tunning) service offered by DarkFrame. https://www.darkframeoptics.com/product/skywatcher-heq5-hypertune

According to their website, they claim their hyper-tunned HEQ5 can do 5 minutes unguided subs with a SW 200P newt (must be heavier than my 115) and its RMS can be as low as 0.42 arcsecs. Has anyone had their HEQ5 serviced by them? What are your experience so far?

Alternatively I've been thinking about selling the HEQ5 and get a new mount with a higher payload capacity/more accurate out of the box tracking. The iOptron GEM45-EC seems very nice on the paper. The reviews while not that many on the web have been quite favourable. The downsides are that it's out of stock due to supply disruption by Covid and it's a lot more expensive than the other option (£2,850 as opposed to £600). Is it worth upgrading from a HEQ5 to this mount for the setup I've got? What sort of average RMS can I expect? Also there is the plain GEM45 without the encoder and it's £900 cheaper. What kind of performance delta will I see between the plain version and the encoder one?

Many thanks.

Edited November 23, 2020 by KP82

[Erling G-P]

Try doing a search for 'darkframe'.  There's quite a lot written about them and people seem to have varying experiences.  No personal experience with the iOptron, so can't help there.

[Skipper Billy]

The APM 115 weighs about 6.5kgs I think.

The HEQ5 should be good for an imaging rig of up to about 11kgs so unless you have a massive guide scope and incredibly heavy cameras and filter wheels etc you should be well within the capacity of the mount.

It sounds like your original guiding wasn't that good and its got worse with extra weight which to me would suggest either a balance issue or backlash or both.

If you have had the mount apart in the past then you know how it works and it might be worth having a look at this guide and seeing if you can remove any backlash. The Heq5 should guide well below 1" total RMS easily under reasonable seeing conditions if it is set up properly and should easily cope with the APM115.

 

 

[KP82]

1 hour ago, Skipper Billy said:

The APM 115 weighs about 6.5kgs I think.

The HEQ5 should be good for an imaging rig of up to about 11kgs so unless you have a massive guide scope and incredibly heavy cameras and filter wheels etc you should be well within the capacity of the mount.

It sounds like your original guiding wasn't that good and its got worse with extra weight which to me would suggest either a balance issue or backlash or both.

If you have had the mount apart in the past then you know how it works and it might be worth having a look at this guide and seeing if you can remove any backlash. The Heq5 should guide well below 1" total RMS easily under reasonable seeing conditions if it is set up properly and should easily cope with the APM115.

 

 

The APM 115 is actually 7.6kg including the rings and dovetail. So with my DSLR, FR/FF, 2-inch extension tube and 50mm guiding equipment it's almost 11kg. The backlash seems to be worse with the added weight according PHD2 guide assistant.

Since this isn't a permanent setup, I sometimes don't spend enough time on balancing (especially on the DEC axis) if the forecast shows the clouds will be rolling in during the later part of the night. I'll give it a few more tries since the iOptron is out of stock until late Dec anyway.

Edited November 24, 2020 by KP82

[alexbb]

You can read my review about the GEM45 and also about tuning an AZ-EQ5 mount here:

Or about my experience with darkframe

 

To summarize, the GEM45 exceeds my expectations in how is performing. With about 10kg of short scopes, it still guides <0.8" total RMS. Depending on seeing, it can even stay below 0.6" total RMS for most of the session. I'm disappointed by the software and mounting the head on the tripod. And you need to be very careful with handling the mount.

On improving the HEQ5, I would not expect miracles from tuning, though I heard about some excellent results for others. I know that that just wasn't the case for me.

On the other hand, there are plenty of tutorials on how to disassembly the HEQ5, you can order yourself new bearings and new worms and replace them.

I ended up spending more on my AZ-EQ5 than to buy a new GEM45 and the GEM45 tracks and guides so much better. Until now, at least.

Here's a typical guiding graph for the GEM45. Not the best, not the worst.

[KP82]

6 hours ago, alexbb said:

You can read my review about the GEM45 and also about tuning an AZ-EQ5 mount here:

 

To summarize, the GEM45 exceeds my expectations in how is performing. With about 10kg of short scopes, it still guides <0.8" total RMS. Depending on seeing, it can even stay below 0.6" total RMS for most of the session. I'm disappointed by the software and mounting the head on the tripod. And you need to be very careful with handling the mount.

On improving the HEQ5, I would not expect miracles from tuning, though I heard about some excellent results for others. I know that that just wasn't the case for me.

On the other hand, there are plenty of tutorials on how to disassembly the HEQ5, you can order yourself new bearings and new worms and replace them.

I ended up spending more on my AZ-EQ5 than to buy a new GEM45 and the GEM45 tracks and guides so much better. Until now, at least.

Here's a typical guiding graph for the GEM45. Not the best, not the worst.

 

Thanks a lot for your very detailed review of the GEM45. This is exactly what I want to read.

A few questions if you don't mind:

1. Does the iPolar work like the Polemaster? I've always been using PHD2 for PA (both drift align when I was in my old house where polaris was obstructed in the garden, and polar drift align). Which one do you prefer now that you've tried the iPolar?

2. Regarding the shortcomings of the iOptron software, am I right that they are irrelevant if I use my PC for GOTO and plate solving with ASTAP to centre the target?

3. I'm not too concerned with the fact I need to use an allen key to attach the mount to the tripod. If I'm imaging in my garden I can just attach it indoor and then carry the whole setup (without the scope or CW) outside. However this gear lock/unlock bit sounds worrying. In your review you said you had to hold the CW bar with one hand while mounting the OTA to the saddle, was it because you had to keep both the RA and DEC clutchers unlocked? If they are locked while installing/removing the OTA, or attaching/removing the head to/from the tripod, there is a big chance that the worm gears will be damaged?

Edited November 24, 2020 by KP82

[alexbb]

9 hours ago, KP82 said:

Thanks a lot for your very detailed review of the GEM45. This is exactly what I want to read.

A few questions if you don't mind:

1. Does the iPolar work like the Polemaster? I've always been using PHD2 for PA (both drift align when I was in my old house where polaris was obstructed in the garden, and polar drift align). Which one do you prefer now that you've tried the iPolar?

2. Regarding the shortcomings of the iOptron software, am I right that they are irrelevant if I use my PC for GOTO and plate solving with ASTAP to centre the target?

3. I'm not too concerned with the fact I need to use an allen key to attach the mount to the tripod. If I'm imaging in my garden I can just attach it indoor and then carry the whole setup (without the scope or CW) outside. However this gear lock/unlock bit sounds worrying. In your review you said you had to hold the CW bar with one hand while mounting the OTA to the saddle, was it because you had to keep both the RA and DEC clutchers unlocked? If they are locked while installing/removing the OTA, or attaching/removing the head to/from the tripod, there is a big chance that the worm gears will be damaged?

1. I don't know, I never used Polemaster, but I heard that it about or exactly the same. If I had direct visibility to the NCP area, I would first use the iPolar, then recheck and readjust with polar drift align.

2. Yes, it's irrelevant with platesolving.

3. As far as I know, the worms are made of brass and the worm wheels of brass (or read somewhere steel, but I don't find this information on iOptron's website). As far as you don't push anything too hard, I don't believe there is any issue if you keep the gear switches locked, but accidents can happen.

[KP82]

1 hour ago, alexbb said:

3. As far as I know, the worms are made of brass and the worm wheels of brass (or read somewhere steel, but I don't find this information on iOptron's website). As far as you don't push anything too hard, I don't believe there is any issue if you keep the gear switches locked, but accidents can happen.

Thanks for the explanation.

Just need a bit more clarification if you don't mind. So basically I can leave the clutchers locked while installing/removing the OTA like I'd normally do on a SW mount without the risk of damaging the gears? Like you said accidents can happen. However I'm more concerned if I have to leave the clutchers unlocked while installing the OTA to the saddle. Then if I forget to re-engage the clutcher, the scope might rotate freely on the RA axis and hit the tripod by accident.

[alexbb]

2 hours ago, KP82 said:

Thanks for the explanation.

Just need a bit more clarification if you don't mind. So basically I can leave the clutchers locked while installing/removing the OTA like I'd normally do on a SW mount without the risk of damaging the gears? Like you said accidents can happen. However I'm more concerned if I have to leave the clutchers unlocked while installing the OTA to the saddle. Then if I forget to re-engage the clutcher, the scope might rotate freely on the RA axis and hit the tripod by accident.

I'm installing/removing the OTA(s) with the gear switches unlocked to prevent any accidents. I suppose you could do that with the switches locked if you are very careful, but I don't want to take any risks.

You should aim to balance the whole system so well that the scope doesn't rotate by itself unless you push it by hand. The bearings are so smooth and allow the mount to rotate so easily compared to the SkyWatcher mounts, there is virtually no chance to forget to re-engage the switches without noticing.