First night out - some questions

[Granada]

So this weekend I finally got a chance to get away from the city lights and put my astrophotography setup to the test over 2 mostly clear, almost moonless nights. Had not done this properly before so encountered some unexpected challenges and wanted to ask a few questions.



The first challenge was dealing with dew - lots of it and everywhere. Now I'm not new to being in nature and have done a fair bit of camping in past, but I noticed all my equipment dewing up and wondered if this is a common occurrence, and what others do to protect their equipment from dew (especially electronics like laptops)? I resorted to wiping everything down with a cloth every few minutes but could not completely stop the guide scope from dewing up and even the SW 120 ED Doublet Refractor which has a dew cap wasn't completely immune.


Another question I wanted to ask was to do with alignment - polar and star alignment. I spent a few hours in daylight making sure the polar scope was properly calibrated to carry out the polar alignment at night, which went well. But I didn't realise just how faint the 4 stars asterism was and therefore difficult to locate, so I gave up on polar alignment after an unsuccessful search lasting about half an hour. How does everyone else go about doing this, and what's the point of it anyway? If I'm star aligned properly and using a guide scope & cam, does polar alignment even matter?


On the topic of star alignment, I've been improving over time, and am able to recognise the 3 stars I typically use for this: Canopus, Achernar & Sadalmelik (not entirely sure if I'm always right in locating Sadalmelik though). The mount (EQ6-R) does a pretty good job of getting me near each of the 3 stars, but it takes a bit of additional adjusting to centre them. However once I'm aligned and choose my next target, I always need to do extra adjusting to get the object in view and centred. Is this normal? My initial expectation was that once you're aligned, you don't need to do any more adjusting - you just press a button and the scope goes to your desired object and centres it dead on. Not sure what the norm is in this respect.


Finally, I'm using a DSLR and was wondering if there is a free guide available online with suggested settings for taking photos of various planetary and deep sky objects?



Thanks and clear skies!

[peter_4059]

I use a half cardboard box over the laptop. That traps in some of the heat from the laptop fan and keeps everything dry. Another options is to get a shower tent and set the laptop up on a table in that. Most of these are big enough to sit in which also keep you warmer. For the optics you will probably need some dew heaters and a controller. You can purchase these or make your own.



There are a few options including drift aligning and plate solving solutions like Pole Master and Sharpcap. Drift aligning is free and quite good once you get used to it. PHD2 is a free guiding software package that has a number of polar alignment options including drift alignment.



Since you have a Skywatcher EQ6 and are already using a laptop, you should consider using EQMOD. This is a lot easier in terms of creating a pointing model and you can progress to plate solving quite easily meaning you don't need to worry about alignment stars. As you are using a DSLR I think you have a few free platesolving options (BYEOS and Astrotortilla) however I don't use a DSLR so you would need to look into these.




Not sure however take a look at the graininess in your images and adjust the ISO to keep this under control. I think ISO800 is a reasonable starting point for the Canon DSLRs. Use the histogram to adjust the exposure - don't clip the white point.


Hope that helps.

Peter

[silv]

+1 to all.
The location also matters re dew. If you can find a grass-less area for your setup.
Since you drive anyway, instead of a cardboard box you can also use a plastic container with which you transported the little pieces and things to your setup location.

Re aligning and Goto precision without Octans: a compass helps. Include the magnetic declination /variation of your location.
If you're at the location during "solar noon", i.e. the middle of the day, you can use that method to mark the tripod leg locations on the ground.

A builder's level helps with tracking precision, too, because the mount has to be level. And balancing the scope well is necessary.

Getting familiar with "drift align" would be beneficial, as well. A search here on IIS for drift align should get useful results. In short: depending on the direction the star drifts out of view to, you adjust the mount setup like altitude and South orientation.

The Goto engines are great for visual use. But photographic use of mount and scope do need extra precision. Lastly, you don't have to aim for 5 minutes exposure time right at the beginning. Stacking several shorter exposures eventually get you somewhere in the resulting image, as well.

Re settings for DSLR: you can use "daylight" for white balance and "spot" for metering mode . Regarding ISO, have a read here http://dslr-astrophotography.com/iso-dslr-astrophotography/
The article also suggests ISO settings for major brands & models.

If you have an outdoor place at home, you can practice all this at home so you develop a routine, saving you time and nerves when you get out to a dark location, again.

Steep learning curveS are ahead. And mainly: a lot of fun under the stars!

[Startrek]

The guru of DSLR astrophotography is Jerry Lodriguss . His site is astropix.com and you can find everything you need to know about DSLR astrophotography
I purchased a few of his books on line and thoroughly recommend them
Cheers

[multiweb]

That made me smile when I read your post. The first night out for me was excitement as well quickly followed by dew then wtf is happening now. :lol: Yeah dew is the first thing to tackle and keeping your gear, laptop etc... covered so I got a tent, a table and a chair. Then took it from there. ;)