My HEM15 has arrived

[Adam J]

1 hour ago, adyj1 said:

£39! - that's an excellent price. I have similar 12v 8AH LiFePO4 batteries that I bought last August and paid £48. I was allowed to take two on a Virgin flight to the US - they had to carried in hand luggage, so just as well they are very light.

I also got a dedicated LiFePO4 charger from Amazon for £30.

I'll be using it to power my HEM27 in the field (bought after the US trip).   [ weak attempt to get things back on topic 😉 ]

Ady 

Yes I have taken them on a Ryan Air and a easyJet flight in hand luggage without issue. In the UK they did not even look at them. But in Spain they removed them and took a look at the capacity. All good. 

[Celerondon]

23 hours ago, fireballxl5 said:

Not so if flying under CAA regs,  limit is 100Wh for  "Spare batteries for portable electronic devices (including metal devices) containing lithium metal or lithium ion cells or batteries carried for personal use". See

https://www.caa.co.uk/passengers/before-you-fly/baggage/items-that-are-allowed-in-baggage/

 

This is interesting!  The Canadian regulations actually seem pretty consistent with the FAA regulations and even use similar language.   I am trying to understand why you follow the third section rather than this first one in the Canadian regulations that you linked.

”Spare batteries for portable electronic devices containing lithium ion batteries exceeding a Watt-hour rating of 100 Wh but not exceeding 160 Wh when carried for personal use.

No more than two individually protected spare batteries per person may be carried.”

This first section matches the FAA guidance that we follow in the USA.  
 

Here is Air Canada’s guidance on this topic.

”2 lithium ion batteries with a rating of 100 but not exceeding 160 Wh”

 

I seldom hear the term “Lithium Metal” batteries used in but I Googled up this explanation for the difference between lithium metal batteries and lithium ion batteries.

Don

 

Edited February 23 by Celerondon

[fireballxl5]

2 hours ago, Celerondon said:

”Spare batteries for portable electronic devices containing lithium ion batteries

This para seems to be with reference to devices that actually have a removable battery integrated into their design,  such as a laptop. 

2 hours ago, Celerondon said:

in the Canadian regulations that you linked.

My link and quote was from the UK's Civil Aviation Authority, not the Canadian authority🙃

When it comes to civil aerospace rules & regulations there is much crossover and duplication of texts,  just under local (National usually,  sometimes regional) document management controls.  This is,  at least partially, in recognition that civil aircraft operate in many jurisdictions and we all need to follow the same fundamental regulations for everyones convenience. 

Regards,  Andy

 

PS, still very interested in the HEM15 so would welcome any further feedback on performance and usability. 

Edited February 23 by fireballxl5
added PS

[bomberbaz]

Some very useful information on this thread, I have the Celestron Lithium 13.2 Ah LiFePO4 Powertank Pro | First Light Optics which I believe meets flight regulations. 

I have setup the imaging rig (details below) but I haven't had a go with it yet. Forcast is for clear spells later so I am just going to have a bash M81, 82 and the garland.  Right now as @Ags I am interested in tracking and seeing how the RNS is. Also bought an auto focuser so want to see how that works and will be running it all from my local network rather than direct connection so want to see how that behaves. No further hijacking, I will report how I get on in my own thread below if anyone is interested. 

)

[Ags]

I have had a couple of sessions with the new setup and had many rainy nights to cogitate, so I think I can sum up my feelings about the HEM15. I really like this mount (used only in combination with a diminutive ASIAIR Mini) - aligning the EQ mount is really easy thanks to the good mechanics of the HEM15, and the clever Air software. Thereafter gotos assisted with plate solving are not merely accurate, they are exact and verified. Guiding in my very limited experience "just works". There seems very little backlash, if any when I was panning about the Moon. The mount is silent and obviously up to the task of swinging my undemanding loads around.  The HEM15 and Air both draw very little current. This is a massive upgrade over the AZ-GTi, and I am very happy with my purchase.

[Celerondon]

1 hour ago, bomberbaz said:

Some very useful information on this thread, I have the Celestron Lithium 13.2 Ah LiFePO4 Powertank Pro | First Light Optics which I believe meets flight regulations. 

I have setup the imaging rig (details below) but I haven't had a go with it yet. Forcast is for clear spells later so I am just going to have a bash M81, 82 and the garland.  Right now as @Ags I am interested in tracking and seeing how the RNS is. Also bought an auto focuser so want to see how that works and will be running it all from my local network rather than direct connection so want to see how that behaves. No further hijacking, I will report how I get on in my own thread below if anyone is interested. 

)

I don't want to highjack this thread into a regulatory rabbit hole, but things will depend on which airline you fly with.  The 160Wh limit is specified by CAA.  But, depending on which airline you use you can either carry two 160Wh batteries, one 100Wh battery, or perhaps something in between.  The relevant CAA regulations were linked earlier in this thread and the FAA regulations are easy to find but both authorities say that different airlines such as British Airways have final say so about batteries over the 100Wh capacity threshold.  At first, I thought that British Airways might follow the lower limit but then I found this page.  So, it seems as if most major carriers allow two 160Wh batteries and according to the British Airways guidance and other sources, you "do NOT need to contact the airline or inform staff at the airport that you are carrying this item." 

Don

[bomberbaz]

3 hours ago, Ags said:

I have had a couple of sessions with the new setup and had many rainy nights to cogitate, so I think I can sum up my feelings about the HEM15. I really like this mount (used only in combination with a diminutive ASIAIR Mini) - aligning the EQ mount is really easy thanks to the good mechanics of the HEM15, and the clever Air software. Thereafter gotos assisted with plate solving are not merely accurate, they are exact and verified. Guiding in my very limited experience "just works". There seems very little backlash, if any when I was panning about the Moon. The mount is silent and obviously up to the task of swinging my undemanding loads around.  The HEM15 and Air both draw very little current. This is a massive upgrade over the AZ-GTi, and I am very happy with my purchase.

Ags, what is your guiding speed setup on the air app. Mine is currently 0.9 as that is what it was for the AZ Gti but I am wondering if the lower 0.75 might be more preferential to the HEM15!

[Ags]

No comment  ... I don't know enough about guiding to give a good answer, and I haven't had enough time under the stars to find what works better or worse with this setup.

[vlaiv]

12 minutes ago, bomberbaz said:

Ags, what is your guiding speed setup on the air app. Mine is currently 0.9 as that is what it was for the AZ Gti but I am wondering if the lower 0.75 might be more preferential to the HEM15!

I would argue that no mount needs that high guide rate.

What is wrong with guiding at x0.25 for example?

Just to put things into perspective - even if you guide at 0.5 second intervals (which is very very fast guide cycle and probably unnecessary) - you can still correct for 1.875" of error in single correction - that is almost two arc seconds of drift or whatever needs to be corrected.

As you see - there is plenty of "corrective power" in x0.25, but such slower guide speed is much easier on the mount and your setup. From physics we know that F=ma, or force is equal to mass times acceleration. On the other hand, acceleration is change in speed per unit time. If your pulse is x0.9 of sidereal - it is very high speed change and very short pulse - that means much more acceleration (or deceleration in case of RA axis and correction in different direction than motion of the mount) which causes jerk on your setup and introduces oscillations that need to dampen down (and in general cause issues with FWHM of your stars).

[bomberbaz]

1 minute ago, vlaiv said:

I would argue that no mount needs that high guide rate.

What is wrong with guiding at x0.25 for example?

Just to put things into perspective - even if you guide at 0.5 second intervals (which is very very fast guide cycle and probably unnecessary) - you can still correct for 1.875" of error in single correction - that is almost two arc seconds of drift or whatever needs to be corrected.

As you see - there is plenty of "corrective power" in x0.25, but such slower guide speed is much easier on the mount and your setup. From physics we know that F=ma, or force is equal to mass times acceleration. On the other hand, acceleration is change in speed per unit time. If your pulse is x0.9 of sidereal - it is very high speed change and very short pulse - that means much more acceleration (or deceleration in case of RA axis and correction in different direction than motion of the mount) which causes jerk on your setup and introduces oscillations that need to dampen down (and in general cause issues with FWHM of your stars).

Thank you vlaiv for the explanation, to be honest I wasn't entirely sure how guiding speed works but now it is clearer. I will try at lower speeds and see how I get on.

I only picked up the 0.9 from someone on here who said they used it on the AZ Gti so I just adopted it & never really questioned it.

Thanks

Steve

[Ags]

Actually, what is this guide speed you speak of…? I don’t see such an option in the user interface?

 

 

 

[Adam J]

4 hours ago, Celerondon said:

I don't want to highjack this thread into a regulatory rabbit hole, but things will depend on which airline you fly with.  The 160Wh limit is specified by CAA.  But, depending on which airline you use you can either carry two 160Wh batteries, one 100Wh battery, or perhaps something in between.  The relevant CAA regulations were linked earlier in this thread and the FAA regulations are easy to find but both authorities say that different airlines such as British Airways have final say so about batteries over the 100Wh capacity threshold.  At first, I thought that British Airways might follow the lower limit but then I found this page.  So, it seems as if most major carriers allow two 160Wh batteries and according to the British Airways guidance and other sources, you "do NOT need to contact the airline or inform staff at the airport that you are carrying this item." 

Don

You have to be really careful, not all will allow over 100Wh and some will allow single 160Wh but not allow a total (for all batteries) over >300Wh so you would not take two 160Wh batteries. I keep it simple, everyone will let you take a 98Wh battery on a plane in hand luggage, you cant get tripped up by it. 

But honestly that aside the Celestron power tanks is £235....what I suggested above is £100 for two batteries of 98Wh each for a total of 196Wh and that price includes a charger why anyone would pay for that power tank is beyond me unless you really did not pay attention in your GCSE physics and cant wire a battery to a connector and I really doubt that applies to very many people in this hobby.  

As this has Hijacked the HEM15 thread for too long now I have made a new thread here:

That way we can get back to discussing the HEM15 which I want to hear more about  so please move battery discussion to the new thread. 

Adam

 

Edited February 24 by Adam J

[bomberbaz]

1 hour ago, Ags said:

Actually, what is this guide speed you speak of…? I don’t see such an option in the user interface?

 

 

 

look under the mount icon and you find it there

[Ags]

I have a few more bits coming for my setup. A couple of finder shoes - for my ZS66 and C6, so that I can mount the FMA135 on those tubes for guiding purposes. Then getting an additional SCT-T2 adaptor because I lose stuff. Also got an amici diagonal so the FMA135 can be used as a visual finder on overseas trips (not sure about the backfocus though).

[Ags]

20 hours ago, bomberbaz said:

look under the mount icon and you find it there

Looks like I am using 0.5 guide speed. I was using a guide exposure of 0.5s and 1s - I didn’t notice much difference between them.

Edited February 25 by Ags

[Elp]

I've found if I change from 1/2s and it's currently guiding say around 1.2 RMS, changing to 0.5s guide exposure usually brings the RMS down at least 0.3-0.4 pretty much within 30s or so. But there needs to be minimal thin cloud to be able to guide exp for 0.5s. The lowest RMS I've had is 0.6 at 120mm guide focal length. Part of me thinks though at such short exposure it's just chasing the seeing, I usually keep it at 1s.

[Ags]

I was quite impressed I could guide at 0.5s. 

I do however think this level of cloud is unfair. When I was growing up in South Africa I had a little book of astronomy that talked about "crisp, clear winter nights" in the UK. Coming to Europe I feel cheated!

We have made up our minds to move to Greece next year to join family members there. We should see a few more clear nights and be a couple of bortles darker. But we will be poorer! Good thing I got this round of purchasing in now

 

[bomberbaz]

On 26/02/2024 at 18:53, Ags said:

I was quite impressed I could guide at 0.5s. 

 

Same here, just checked it again and it is consistantly guiding at under 0.8 and sometimes as low as 0.5.  Bearing in mind I only have a 120 FL guide scope I am pretty impressed with this. 

[Ags]

Attached my new finder shoes to the C6 and ZS66, so I have more scope options with the HEM15, as I can mount the FMA135 as guider/finder scope on these scopes now.. Not impressed with the build quality of the C6 - finder holes are obviously out of true (no surprise as I was never able to align the RDF).

[Ags]

Spent an hour and a half imaging the owl. My scope doesn't like bright stars. Also first time using Starnet++.

Edited March 6 by Ags

[Ags]

Not too impressed with the results from the Long Perng 90 (plus f6.3 reducer), so I am trying M51 with the ZS66 tonight. I had some issues polar aligning - try as I might I could not get the Air to polar align with the ZS66 (I had reset focal length to 0 so it wasn't carrying over the focal length from the LP90). Eventually I resorted to polar aligning with the guide scope, which worked fine.

I am dithering but I have this set to the minimum values as I have no idea what to set it to. It seems to have helped on the very stretched image above! The background is smoother than I usually get.

Edited March 6 by Ags

[Ags]

I tried the mount with my C6 tonight, a less than successful endeavour! I wanted to see if the mount would cope with a light breeze and the relatively large C6 and dew shield, and the short answer is no. Guiding was all over the place and exposures of any length had wind-induced trailing. Obviously a scope-mount combo for the most serene evenings only

I was also hoping to see if plate solving would work with the ASI485MC and the C6. Even with the f6.3 reducer, the FOV is on the edge for AsiAir plate solving. I made several attempts but could not solve any view, nor could I polar align with the main scope.

Also, I managed to spend an hour trying to find focus!

[Elp]

If the setup is shaking or your sensor is noisy (I assume it is as it's uncooled and I've used the 485MC for DSO imaging) the air will not plate solve so PA will also not work. You can try increasing the exposure duration to something like 5 seconds, maybe more so the stars saturate on the small pixels of that camera, it'll then see more stars and not confuse noise for stars which can happen with uncooled cameras and cause it not to plate solve. But I suspect the wind also played a part.

[Ags]

Yes, I was also expecting the wind was a problem for plate solving, but I was hoping the setup could stand up to a bit of a breeze. One possibility to improve things is upgrading the current  light Berlebach Report tripod to cheap but solid skywatcher steel tripod.

I didn't know I could change the exposure length for polar aligning. Thanks for the tip!

[Elp]

Generally if the wind average forecast is over 10, maybe 15mph I don't bother setting up for imaging. And that's using probably the shortest BB Uni you can buy. But as you say, a small refractor or a camera setup may fare better. Sometimes the clear skies are too tempting to ignore.