How many dark frames?

[RSM]

6 hours ago, Moonshed said:

Thanks Richard. I note your comment about using Pixinsight, lots of people here recommend it. I checked out their web site and was a bit taken aback by the price, €230 + VAT. not sure but think the VAT would be 20%? That would bring the price up to €276 which is outside my budget. I am disappointed because the programme looks so good, looks brilliant in fact. Oh well, I shall just have to make do without it as I am sure many others do, after all it is a lot of money.

Hi again, yes it's a lot of money, I think I bought it when the euro was a bit better rate than it is now (1.4 I think!) but it does everything I need (so far). Also, I'm sure I was charged the 230 incl VAT ( the website was not 100% clear). I signed up for the 45 day trial (used to use GIMP and DSS) but before I started the trial period I captured loads of subs of different things to make sure I used the trial period to its fullest. By the time my 45 days were up, it was a must buy for me. It's not the only route but it worked for me. I don't have an old version of PS and I didn't like the "rental" model they now have for the latest version. They update regularly and you get all the updates free. Also there are loads of tutorials on you tube to learn how to use all the different functions. Highly recommended but it is costly. 

[wimvb]

I'm pretty sure that the 230 € is including VAT.

Just a clarification on the licensing fee and upgrades.

This is what it says on the PixInsight website (from their FAQ):

"When we release version 2.0, the price of a commercial 2.x license for existing users will be directly proportional to the time of use of their 1.x licenses.

For example, a user who purchased his or her license a few months before the 2.0 release date will have access to the new version at no cost. A user who purchased a license a few years before the 2.0 release will have to pay the full 2.x license price. These examples should not be taken literally; the exact terms of our upgrade policy will be determined when appropriate, but you get the idea."

and also:

"Commercial users have access to all software updates for PixInsight version 1.x at no charge. This includes all bugfix, maintenance and improvement releases of the core application, and all standard modules that we publish for this version. Of course, we refer only to modules developed by the PixInsight Development Team (these are what we call standard modules); we cannot speak for modules authored by third-party developers. New standard modules extend PixInsight's functionality at a constant rate. "

On the other hand, version 2.0 is not even scheduled yet:

"Right now it's hard to say anything precise, but definitely not before 2017. Perhaps 2020... "

When I bought my license, I compared to PhotoShop. As Richard, I didn't like the rental model much. Furthermore, you still need a stacking program. PixInsight includes this, and it works great.

All in all, PixInsight seems to include everything I need. No need to switch between programs.

But I do advise you to get a feel for different software packages. The philosophy of image processing differs between the various packages, so have a look at which appeals to you most.

Good luck

[Moonshed]

Okay, appreciate the input re Pixinsight. I think it is something I will buy a little further down the road when I have got some experience behind me and can take full advantage of it. Meanwhile I will do what I can in PS.

Thanks

Keith

[MattJenko]

45 minutes ago, Moonshed said:

Okay, appreciate the input re Pixinsight. I think it is something I will buy a little further down the road when I have got some experience behind me and can take full advantage of it. Meanwhile I will do what I can in PS.

Thanks

Keith

Perfect attitude. This is such a vast hobby requiring so many skills, it is very sensible to take things slow and push what you have before simply buying stuff.

[Jerm503]

On 15/08/2016 at 11:51, Stub Mandrel said:

Don't forget that darks will also get rid of hot pixels - I have about 40 or 50 of these on my 450D that would otherwise show up as extra stars.

I have done an experiment on ISO levels and it shows advice here appears to be right while some respected websites are wrong. The experiment shows ISO800 is much less noisy than ISO1600 for my camera on long exposures although theory (based on short-exposure noise measurements) suggests the opposite should be true.

Same I did a simple experiment, processing the same image twice once with 60 darks (probably over the top) and once with no darks. I know which is which and this might bias my feeling about which is noisier. Which one do YOU think is the noisier image - I will then reveal which has no darks.

 

Nice! Thanks for showing us the comparison! It shows me that dark frames will be important (the difference is clear to me), but not until I start getting some better images in the first place. That's exactly what I was trying to figure out!

[alacant]

On 15/08/2016 at 17:21, Moonshed said:

My camera is a Canon EOS 1100D.

Hi. Our advice is NOT to take dark frames. With our 700d they introduce more noise and are a pain to produce anyway due to the impossiblity to get the correct temperature.

So, instead -and less noise IMHO- take the light frames but in between each, move the telescope a few pixels (called dither). Also take flat frames and bias frames. There are imaging apps withich will do the dither for you. Maybe start another thread for that?

Cheers and HTH.

[ollypenrice]

I find Pixinsight very hard work for stacking and calibrating whereas AstroArt is easy, fast and logical. On two occasions guests have tried to convert me to PI for stacking and gave demonstrations which, in both cases, didn't work! 

Olly

[bottletopburly]

+ 1 for dithering as others have said ?