HEM15 with C/W

[bomberbaz]

Has anyone got the counterweight and bar the the HEM15? I ask because when I searched FLO's site for the recommended bar and weight the dimensions look small compared to what they add to mount capacity.

The bar looks to be circa 15-20cm and the c/w is only 2kg. Yet the specs state a near 4kg difference between the two options

Without c/w =  8.17kg

with c/w = 12kg

Has anyone used the setup with and without c/w, what comparisons (if any) can be drawn from experience using it and how does the c/w effect (if at all) the tracking?

Cheers

steve

[Elp]

With a HD mount the CW has more to do with the setup not falling over.

Guiding as is from my comparison to my gem28 (same imaging scope payload) is worse if you compare the RMS figures but so many factors can contribute to this, one of the main being where the scope is pointing. Typical average I'd say is around 0.7-0.8 RMS with the hem15 but because you have to guide fast it's constantly adjusting as the seeings changing, with the gem28 I can 2-3s guide and comfortably get down to 0.6-0.7 RMS. Balance makes a huge difference with ioptrons, even a mm change in CW height position makes all the difference in balanced to unbalanced state, and the times I've used my hem15 I haven't set the Dec balance perfectly. The hem15 however settles extremely quickly say after dithering (literally maybe 10-30 sec back to average RMS figures whereas the gem takes maybe 1-3 minutes). Been able to do 5 minute exposures with the hem15 no trouble at all despite the RMS output. The real test for me is imaging over 1000mm and seeing how it compares.

Regarding bar, you could DIY an all thread and make it whatever length you want, but if youre going that sort of payload weight it'd be better to get the next weight class mount up.

[bomberbaz]

Thank you @Elp for the explanation, with the set up I am considering the load would be close to 8kg so would prefer to air on the side of caution.

I do have a suitable short bar and a 1.25 weight, so I think that would likely be enough to ease both my mind and any topple liability. 

At 600 fl I wouldn't be overly concerned over tracking if it's under 1rms. 

As you know I have the az gti and this is the item under threat along with the 72ED. 

So based upon you owning both mounts, are you happy with the performance of the hem15 vs the Az gti?

Cheers

Steve.

[Elp]

For my compact needs (the mount can be packed with the scope items in one bag) it's almost perfect. Haven't tried it long enough to be certain but immediately being able to image 3-5 minutes without issue with my SY135 certainly looks good, with any setup on the azgti pushing beyond 2 minutes can be hit and miss over the course of a run. It handles my C6HS setup fine too whereas the azgti struggles with it even for short subs. I wanted to test my 102mm before deciding (as I have the gem28 also so I am also debating about whether to let go of it, the hem being it's replacement).

An alternative which I was considering prior was the ZWO AM3 but they took forever to ship in, and I couldn't justify the 500 odd extra for the HD Dec axis, it also seemed slightly larger and slightly more power hungry. If I want with the ioptron I can just quickly PA with an air, then just rely on the hand controller to browse the skies as a visual setup (or even AP on minimal power usage if carrying around excessive battery packs off site is an issue) whilst a secondary setup is running.

There's no real direct comparison with the azgti, but I do find my WO wedge much better still to PA with. The ioptron is so much better engineered as a mount (other than the azimuth locking bolts, I don't like them, they seem to bite into the bottom plate and it knocks off PA so I usually leave them very softly locked after PA (practically loose)). It's nearly whisper quiet in comparison. It's direct equivalent would be the AM3.

Edited October 11, 2023 by Elp

[bomberbaz]

1 hour ago, Elp said:

There's no real direct comparison with the azgti, but I do find my WO wedge much better still to PA with. The ioptron is so much better engineered as a mount (other than the azimuth locking bolts, I don't like them, they seem to bite into the bottom plate and it knocks off PA so I usually leave them very softly locked after PA (practically loose)). It's nearly whisper quiet in comparison. It's direct equivalent would be the AM3.

You have confirmed what I thought and seem to remember reading some of these points before. (maybe yours even!) I think the HEM15 is my way forward for my objectives.

Anyway, thanks for the reply, most helpful.  

regards

[Elp]

I think there's a thread similar to this on here. One thing I'd add, it has two mechanical range adjustment settings, this is fiddly to do and I would never attempt to do it outdoors. The AM3 wins in this regard as I believe it has 90 degree operation range via two range adjustments whereas the hem15 is limited to 15 to 65 degrees latitude via it's two range adjustments. But I gauged if I'd ever take it to latitudes beyond that and likely not so suited me, for alt az I've got the azgti or manual altaz mount.

Edited October 11, 2023 by Elp