nakbrooks

Just a follow up to this. I've plotted data from both instruments over a period. It is not practical to correlate their readings directly because obviously they are doing different things: SQM is essentially a photometer and is purely measuring "darkness", whereas CloudSensorII is detecting cloud cover (by comparing sky temperature to ambient temperature). In principle there should be some correlation (as cloud cover will tend to magnify light pollution because it will reflect street lighting, etc) but there are confounding variables - notably the Moon will affect SQM but will not affect CloudSensorII. Really they are complementary tools. CloudSensorII is useful in determining whether it is worth attempting to image and its rain detector will enable the roof to be closed (I'm assuming remote automated operation here) whereas SQM places some metric on sky quality which is useful in assessing images taken. I'm going to make an attempt at calibrating SQM in October, weather permitting, as the Moon will be both New and below the horizon at my site in the middle of the month (and if I wait until after 1.00am the church and street lights in the village are off). It will be interesting to see whether SQMs reported naked eye limiting magnitude actually corresponds to what I can see for myself in the sky.

I have both Unihedron SQM/LE and Boltwood CloudSensorII sky quality sensors but so far haven't found an easy way of correlating them against each other or calibrating them, so I don't know how accurate their absolute readings are. Any advice would be welcome. Nigel

Very impressive George.

You are right. It will be good to be able to move on from engineering and start doing astronomy. I estimate it will be a good 21 months from first hole in the ground to first light. Domes complicate things.

Yes, I hope to move full-time to France in the next couple of years which is why I built it there. Much better seeing than in South West England where I live now.

Hope no-one minds a bit of flagrant self-promotion: https://www.facebook.com/stratisobservatory My observatory, currently sill being commissioned. Feel free to Like if you are on Facebook. Hopefully I will get to first light by the end of the year and can start producing some decent material in the Spring. It's a long process - partly because of recent very bad weather, partly because of numerous problems with the dome and electrics, but mostly because I can't spend enough time on it given other commitments. Nigel

This has become a bit of a feeding frenzy. Hopefully ASA have now got the message that we are all very supportive of their fantastic hardware and we recognise that Dr Keller has singlehandedly produced some really innovative software to match that hardware. Hopefully ASA will soon respond to give us the comfort we need that the software will continue to evolve, that it will be professionally documented and supported, and that measures will be put in place to protect our investment. I'm going to hold off from further posts to give ASA a chance to respond.

Yes, I'm not suggesting anyone try to reinvent Autoslew/Sequence now; it would just be a comfort to know that this would be possible if, for any reason, Dr Keller was no longer maintaining the software.

The thing that concerns me is the following set of dependencies: 1. ASA hardware is superb, but is not usable without software. 2. The current software (Autoslew/Sequence/etc) seems to be dependant upon a single individual for its development and maintenance, and so far as I'm aware that individual is semi-independant of ASA itself. 3. The current software is not open source, so it is not possible for users or third parties to continue development if (for whatever reason) it ceases to be supported by either the developer or ASA themselves. 4. The hardware/software interface is proprietary and not documented so it is not practical for a 3rd party or users to develop alternative control software. I presume that ASA is primarily in the business of selling hardware, not software. I would therefore have thought that it is in their best interests to publish the driver interfaces so that third party products can control the hardware - this would both increase the potential market for ASA products and also provide comfort that 3rd party control software might become available if Autoslew/sequence ceased to be supported. ASA could consider making the Autoslew/Sequence software open source, but I'm not sure if the IPR is owned by ASA or the develoiper and it would probably open a can of worms from a support perspective if users started altering the source in an amateurish fashion. However the source could be made available for purchase by serious developers and/or escrow arrangements could be put in place so that it becomes open source if it ceases to be maintained by ASA. Nigel

Mark The problem is that a forum is rather unstructured and there is no means of editing each other's posts to enhance and refine a knowledge base. A wiki is the ideal vehicle. I agree that one sponsored by ASA would be preferable, but I think they should focus their limited resources on the printed/PDF documentation if they aren't able to do both. Even with a wiki we will have problems handling different software versions and permutations. It is likely that the people best placed to populate the wiki will be using beta versions while those who are most in need of help will be using the release versions. The wiki will need to clearly identify what version each page is valid for.

I think the problem faced by ASA is that they are trying to package software originally developed for professional and semi-professional users for the broader hobbyist market. The two audiences require a totally different philosophy. Professionals are looking for fast evolution of the product, with features added as soon as they are developed. They are willing to do their own debugging and they can live with poor documentation because they have the technical skills needed. The hobbyist requires a shrink wrapped product that works out of the box with little or no tweaking and is supported by extensive up to date documentation and support. If ASA wish to focus on the professional and semi-professional market then they must make this clear in their marketing so that customers are not misled into thinking they can use the software without the pre-requisite skills. If ASA wishes to also market it's products to the hobbyist they need to invest in the shrink-wrapped product and proper support. It is part of the investment they must make in return for the higher sales they wish to achieve from the wider amateur market. Possibly ASA has underestimated the resources required to do this and are caught between the competing demands of their two customer bases, and do not have the volume of sales to generate the revenue to fully support both. Probably there need to be two versions of the software: 1). A "standard" version, basically a simplified Autoslew, which meets the needs of the typical amateur, is stable (max one release per year) and comes complete with documentation, wizards, videos, etc. 2). A "professional" version which comprises the full suite of software, is quite possibly open source, and is supported with developer toolkits to enable professionals to integrate it with 3rd party h/w & s/w. If an amateur wants to use the professional version then caveat emptor. The difference in philosophy is akin to the Unix and Windows markets. Unix geeks think it is normal to have to compile the operating system before it will work (but they can tune it to exactly meet their needs); Windows users think that is madness - they aren't interested in operating systems, they just want to use their computer. As a further thought, as the hardware is useless without the software, either the software should be open source or some escrow arrangements should be in place for the benefit of a user group. Otherwise if (God forbid) anything happened to Dr. Keller or ASA itself our investment in ASA hardware would soon become valueless. Nigel

Very nice Luke. It's a long process getting an observatory set up (I have dome problems to resolve before I can get back to commissioning the ASA equipment) but hopefully once everything is sorted I will enjoy similar results from my ASA 16" Cassegrain.

Out of interest I use this http://admaccessories.com/Miscellaneous_Max_Guider.htm to piggyback my secondary OTA (125mm Hutech/Borg) on my primary OTA (ASA 16" Cassegrain). It allows easy but secure adjustment on all axes both for balance and co-alignment with the primary. I would not suggest it for attaching a heavy primary OTA to the mount though. Even though it is very solidly built it would introduce unnecessary potential for flexure. Nigel

I'm very surprised that you haven't had a response from ASA for weeks. I've found them very responsive (although it does depend on who you email). A telephone call should get an immediate response.

Good point. There is an auxiliary power input (for camera, etc) and the main mount power input.

I have had exactly the same noise and vibration on my DDM85XL occasionally when it was supposedly in balance and tuned, although this has always been after I have re-balanced. Not sure what causes it but I have managed to get rid of it by playing with the tuning.

Personally if it were my one I'd be worried about invalidating the warranty by doing too much DIY surgery. I'd leave it to ASA to sort out. Just a thought.

Yes, but for high-end mounts (e.g. DDM85XL) designed primarily for fixed installations I think RS232 should be an available option as many people would use dedicated PCs that either have add-in serial cards or built-in serial ports (a dedicated PC with an add-in serial card can be got for only a few hundred pounds after all). I use a wide temperature range industrial PC with 6 serial ports (none of which I am able to use as all the ASA kit uses USB). I am a firm believer in the KISS principle (Keep It Simple, Stupid); there are enough variables involved in amateur astronomy as it is, without having to struggle with the hardware/software issues involved in getting USB to work reliably through daisy-chained hubs with different combinations of Windows/vendor drivers and multiple competing devices sharing the same USB bus.

Bit difficult to say as USB problems can have so many causes. I had a similar drop-out issue but it turned out to be a USB over WiFi converter causing the problem - nothing to do with ASA. I really think there is an argument in favour of providing a serial interface as an option as this is much more reliable because it is low tech.

What is the total weight of your payload Lukas (excluding counterweights). The DDM85XL can handle a very heavy weight.

What make and model is the OTA? As you say, you should be able to narrow down which component is responsible by rotating them individually.

Has this just appeared or has it always been like this? If it has just appeared, what changes have you made recently to the optical train?

It appears your problem is still getting correct balance at all attitudes. Until you get as near perfect as possible balance with the OTA in all attitudes it is not really worth exploring other issues as you won't know whether it is the balance or something else causing the problem. Once the balance is sorted (using the Autoslew balance function) then, if the problem persists, you can explore other possible problems. Probably tuning is the next thing to look at after balance. As always, change only one thing at a time so you don't complicate the diagnosis.

Thanks for that Bill. Exoplanet transit detection is where I would plan to start, so that accords with your advice. I'm hoping that my observatory will be pretty autonomous (it needs to be as it is in the Pyrenees and I am in Wiltshire) so, if all goes well when fully commissioned, I hope to be in a position to do some useful stuff.

and the 85 Pro/XL has no alignment at all - it is bolted rigidly to the XL pier and you align the whole pier, a one-time procedure for fixed installations.