Skip to content
How to measure sharpness in your images | Hyperion Astronomy

How to measure sharpness in your images

It is hard, sometimes, to discern if your images are really as sharp as they might be. While your eyes are great to spot the difference between a blob and a sharp star, it is preferable to have some real data to actually analyze. 

Stellar Sharpness Measurement ( One image )

As soon as you download an image from your camera, you can very easily see if your seeing and/or focus are up to par. Just right click on your images and choose Stellar Sharpness Calculations then the size of the zone to be measured. If you choose 512x512 for a fast turnaround. If not, the entire image will be used.

 Here is how you measure a single image

 

measure stellar sharpness with one click

 Measure Multiple Images

Another great tool in PRISM is the "Quality Check (Stellar Images)" under the analysis menu. This tool allows to analysis a whole set of images ( same size and pixel type that is ) in order to understand how the imaging session evolved of the course of a night for example. Here is a quick rundown.

1. Load the tool, check an area of 1/8(for faster analysis) the frame and press OK

2.The output is as follows:

Mean sky background

Median sky background

Seeing calculation

Elongation of the stars

And finally, the actual output of the tool with all the data

Previous article M77 and NGC1055
Next article NGC7331

Comments

Hamza - October 27, 2019

John.
For elongation, you want the smallest number possible, this means you collimation and focus are working well.
For the rest of the numbers, it is a great indication that you tracking and collimation are good as well.

John Monroe - October 19, 2019

Hi Hamza, once I run this tool how do I interpret what the numbers mean?
Thank you, John.

Hamza - October 9, 2019

Thanks Craig. It is a great feature set that will really help you find and only utilize the best data. It is a very quick indicator of how well your system is tuned too. Awaiting images from your new system.

Craig - October 9, 2019

Great tool! I didn’t know about the Stellar Sharpness capability until I saw your post- thanks for highlighting it. I especially like the seeing estimate and it ran plenty fast even though I processed a 4096×4096 image. I have to say that Prism has a really nice set of analysis tools. When I installed my new scope recently I was able to quickly characterize the optical system including collimation and field flatness which saved me a ton of time because I found that no adjustments were needed before going through the whole collimation process. That was especially important for me because the observatory is about 2000 miles from home and my installation window was very tight.

Leave a comment

Comments must be approved before appearing

* Required fields

★ Judge.me Reviews

Let customers speak for us

18 reviews
83%
(15)
17%
(3)
0%
(0)
0%
(0)
0%
(0)
Imaging Made Easy

Prism is my GoTo program for observatory control and imaging. Prism's many features make imaging taking a breeze.

I was concerned about giving Prism a try , especially as its quite expensive. So far Im very impressed and glad of my decision.
Im a beginner at all this so haven't tried other more recommended software, Prism appealed as it seems to do everything instead of using several programs 👍🏻

Great lightweight guide scope

This guide scope replaces a 400/80 that was waaay too heavy for what it did. The smaller 60mm scope does a great job guiding and I can RA balance with just one counter weight now - much better - and it looks like something Ferrari designed

Still learning Prism using Wireless links...

I have much of your software working at this time... I have it parked on my main computer, and a notebook... My main computer is a OverClock computer with 32 Gigs of RAM Clocking presently at 4400MHz with software parked on SSD drives... The rotation dome by NexDome is still not working... Most problems like this have to do with ASCOM Drivers... There is not very much detail information on how to use this software... I have to feel my way to a total operational staus... Second issue... The rain in the San Francisco Bay Area this year has limited my access to my larger telescope (12 inch SCT)... This rain has been so significant, I was force to weatherize my observatory... My goal here is,,, I am trying to remotely control my observatory totally. I have used Netgear Powerline 2000 to handle camera images and discover controlling rules to do that... High speed is vital for images with cameras over 3 Megs... I have both 12 Mega sensors and 24 Mega sensors... I am also using Netgear Nighthawk router and its mating extender to increase control signals to my observatory that is about 100 feet on the side of hill... I am also using Virtual Here software on a Raspberry Pi inside the observatory to solve the USB interface requirements... I started out using Model B and B+ on level 3 raspberry Pi's... I have moved to Level 4 Raspberry Pi to gain access to USB 3.0 technology... Big difference! I hope by early spring to have everything working... Bob Ritter MicTechS

A great program, even for beginners!

I have to admit, I was hesitant to invest in an “all in one” astrophotography program. Being a beginner, I thought the learning curve would be way too steep, but after talking with several friends I decided to give it a try. The first thing I noticed was the logical layout of the main screen. It was very intuitive and easy to navigate. Everything you could need for astrophotography is in this program! Setup of my equipment was quick and easy with no glitches or errors. Everything runs smoothly from capture to the final process. You will surely have questions and this brings me to the next point. Prism’s customer service is second to none! With on line tutorials, a Facebook group and email you will have instant access to knowledgeable users worldwide. My first question was answered directly by the US distributor within a matter of minuets! Take the next step and invest in your future in astrophotography! You’ll never look back!

Greg Hemmings