nakbrooks

If you do a search for the words "balance" and "Autoslew" using the forum's search facility it will turn up several posts giving useful information. One example is: http://forum.astrosysteme.com/index.php?/topic/100-balance-function/

Good one George. That's what I like about photometry/astrometry - plenty of opportunities for the keen amateur with decent but fairly modest equipment to spot things that the professionals may not yet have got around to finding (although in this case obviously they did). I'm getting very frustrated with the delay in getting my observatory in France operational but there's been several weeks of cloud, and it could be some time yet before we have a weather forecast good enough to make it worth the risk of getting people to travel down there from England and Austria.

I think you may have sold yourself short when you said in the other thread (about adding science topics to the forum) that you didn't know how to start with science work! This is a good example of why we need science topics in the forum so these sort of results can be posted and compared between members.

Excellent. Did you measure relative to one or more reference stars?

You're lucky to have got that one George. Most of the country seems to be covered with cloud.

Who is going to post the first photo with ASA equipment? Won't be me, I'm still commissioning:(

Agreed. There are no brakes (apart from manual locking screws) so when the power fails (or indeed if it is just switched off or the motors are powered down) then the axes are free to move without restraint. This isn't a problem if you are well balanced. As good balance is essential to the operation of the DDM mounts any residual imbalance is likely to be very small so any movement after power is turned off should be very slow and very unlikely to cause damage. I'm lucky in having the XL pier (the Z-shaped one) so have full 360 degree movement in both axes without hitting anything so I can sleep easy at night! Should only be an issue if the mount is left outside in a strong wind (and if it is outside I guess there shouldn't be anything to hit).

That's interesting. I have a DDM85XL Premium with about 70kg (140kg including counterweights) mounted, which is well within the maximum of 100kg (excluding counterweights) for this mount. I find it very sensitive to balance - I would have expected a DDM60 carrying much less weight to be more sensitive, not less.

Sounds like we're in a very similar position George. While I'm interested in astro-photography, having recently retired I am looking for the intellectual challenge of doing some science, and I also feel a bit guilty about having spent so much on what would otherwise purely be a somewhat self-indulgent hobby! Like you I didn't know where to start but have found an excellent source of information is "The Sky is your Laboratory" by Robert K Buchheim (ISBN 978-0-387-71822-4). My specific immediate interest is exoplanet detection (using the transit method) and a great introduction to that can be found in Bruce Gary's e-book (http://brucegary.net/book_EOA/ExoplanetObservingAmateurs2ndEdition.zip). I have yet to start any serious work as my new observatory is still being commissioned, but I look forward to spending some time on this through the summer. It is clear from what I have read that if you have the equipment to do good astrophotography then you already have everything you need to do science work. Indeed much science work is less demanding of equipment than astrophotography - in particular small CCDs are fine and CCD flaws don't cause a problem. The challenge is in the technique - it requires great attention to detail. Any background in the experimental sciences would be ideal, but anyone who has patience and a naturally methodical mind can quickly pick it up I believe. I'm currently doing an Open University degree in Astronomy and Planetary Science, but that level of expertise is by no means necessary (and I've only just started the degree anyway, 44 years after my last qualifications - which were rather unimpressive A levels). I was hoping that the ASA forums could act as a self-help group for those who might be interested but are a bit intimidated by mixing it with the experts in the Yahoo forums. Nigel

No responses so maybe no other forum members plan to do science work

The one thing I've learned with DDM mounts is that they are very sensitive to balance so I try not to change anything once I've got a good balance and tune. Also if you start rotating the camera you may have to re-do flats, etc. I did have a rotator to enable adjustment to framing but removed it because my camera has a square CCD so it isn't really necessary. Personally I prefer to keep everything locked solid - there are enough variables to contend with already without introducing new ones!

Would there be support for creating a new section within the forum for Science applications of ASA equipment? The current emphasis of the forum seems to be very much astro-photography, but I am sure that others, like me, would be interested in using ASA equipment for broader scientific purposes as well. Possibly a new section called "Science" with sub-sections for: - "Photometry" (e.g. transiting exoplanets, variable stars, eclipsing binaries, etc) - "Astrometry" (e.g. asteroid and minor planets) - "Spectroscopy" (e.g. solar and stellar spectra) Although there are specialist Yahoo groups already for these topics they tend to be for advanced users and are a bit cliquey. It would be really good to enable amateur ASA users who want to use their equipment for science purposes to compare notes and help each other here. If there is reasonable support for this then maybe ASA would add the new sections? Nigel

I suspect the problem is USB-related (sockets, cable, driver, hub or conflicting virtual COM ports). It would solve a lot of problems if Autoslew and the DDM mounts offered a physical COM port option! However there may also be a balance issue complicating things - Autoslew is very sensitive to balance. Have you checked balance at different mount attitudes to see if it changes much? If you have any off-axis equipment (e.g. a finder scope or a filter wheel mounted at an angle) you may need to add additional counter-weights to get correct balance at all attitudes. For example, I have a rotator which means that the balance changes at different rotation angles because of the off-axis filter wheel; I had to add custom-designed weights to the camera/filter assembly to keep it in balance as it rotates. I normally do the initial balancing with both the counterweight arm and OTA horizontal, then test it again at 45 degree increments for each axis. Then I do a manual tune (with the counterweight arm vertical and the OTA pointing at the pole). Nigel

Yes, try it with only the main mount USB connected (not the mount auxiliary hub and not the covers, focuser, etc) and reboot your PC and cycle the power on the mount. If that works then add the other USB cables back one by one until you find the problem one. If you identify the one that is causing the problem then try the following: 1. Check for any problems in Control Panel / Device Manager. 2. Check you have the latest USB driver from Microsoft. 3. Check if your PC manufacturer has a later USB driver. 4. Check you have the latest driver for your USB-to-COM converter. 5. Check you are using the latest version of the virtual COM port driver. 6. Try changing the USB cable in case the cable is at fault. 7. Check the cable connectors and the PC/mount USB sockets for dirt or corrosion. 8. If you are using an external hub in the connection try with a direct connection in case the hub is the problem. 9. If you have equipment using the ASA USB hub on the mount then temporarily connect it direct instead. 10. If all else fails try using a different PC/laptop I had very similar symptoms (Autoslew reporting random dropping of the USB connection). As I said, my problem turned out to be a virtual USB over WiFi connection. In your case it might possibly be the USB-to-COM converter. After that I have run out of ideas! Nigel

Could be a conflict. Particularly if you are using virtual COM ports over USB for other stuff. What other USB equipment is connected? Try disconnecting one at a time and see if the problem goes away. I had this issue when running a virtual COM port over a virtual USB port over WiFi (possibly unsurprisingly!). When I disconnected that item all my random USB problems went away

If ASA bundle 3rd party software they would obviously have to increase the cost of their own products to cover the cost of the bundled software. I doubt if ASA have sufficient sales volume to negotiate a large OEM discount from the 3rd party vendors so the savings to those who don't have the software would be small and those who do have it already would be effectively paying for it twice. Also, some products such as Maxim come in different versions so ASA would need to decide which version to bundle. If it were the most expensive then this might be more than many users need. If it is the cheapest then many users may need to separately buy the more comprehensive versions themselves. I think it only makes sense to bundle software if it is absolutely essential to the operation of the ASA software and if there are no alternatives available, (particularly freeware ones). Nigel

I'm not at my observatory at present so I can't check, but I'm sure ACC was a separate install, and therefore presumably can be deinstalled using Microsoft control panel. However I've not done this so best if others confirm.

I have the ASA secondary mirror focuser on my Cass 400 but experienced the same problem at first (using ACC). Turned out that the default settings had it focusing far too fast. ASA did a remote control session and adjusted all the (undocumented) settings and it works fine now. No point in me giving you my settings as I assume they are OTA and focuser specific. Suggest you ask ASA for a remote session. Nigel

Can you not simply uninstall ACC if you don't need it?

Fortunately my mirror covers worked fine out of the box, however most of the accessory controller software (covers, rotator, focuser, etc) is very poorly documented. Rather than struggle with it I have found that ASA will set up a remote control session very readily (if you are Internet connected) to fine tune the settings for you. They did this for me with the focuser on my 400mm Cassegrain (the default settings were way off and there was no documentation anywhere about what they should be).

As an afterthought, maybe a physical solution might work (e.g. Foam fastened to the inside of the roof where it might contact your equipment)?

In theory, if your scope is protected against gusts of wind and is well balanced it shouldn't use much power if left with the motors on. However personally I would have a major concern that a power surge or software glitch could cause an unexpected large random mount movement that might cause you problems if you have limited clearance. I have an equatorial (XL) pier and a largish dome so have full 360 degree clearance on both axes without hitting anything - but even so I'm not sure I would leave the motors on when not imaging. Probably best for ASA or someone else more experienced than me to give a definitive opinion though.

When you say powered on, do you mean power on but motors off or power on and motors also on. With motors off I would imagine it would consume next to no power. I would be wary of leaving the motors permanently on, although as my scope is well balanced in a closed dome the motors should be doing no work so maybe that is just my natural caution.

Personally I always keep Windows auto updates turned off and only do a manual update a few times a year at times when I know I have plenty of time to sort out the almost inevitable consequential problems. Different for my personal and business PCs, where I need to keep up to date with the security updates. The dedicated observatory PC is behind a hardware firewall with no inward Internet connection and is not used for web browsing or email, so I am happy to go for months between Windows updates.

Good one George.