Jump to content

Help finding (very recent) archive data

Guest Adam James

Recommended Posts

Guest Adam James

Hello everyone. 

Stumbled upon this community while trying to find some data about the sunspot region 1974 as it was on the 13th of February.

I'm currently doing my final year project for University (read: playing with a SolarMax II 60mm scope) and have reached a stage in writing where I need to get a bit of Physics in!

I'd really like to be able to quantitatively compare some of the images I've taken to the data from SDO/HMI - in particular an exposure taken on the 13th of Feb. In my image, the major spot group in region 1974 shows up very well, as does the surrounding plage - but a majority of the sunspots in the group aren't captured due to (what I think) are resolution problems.


I'd really like to know the sunspot area for the region as it appeared on the day I took an image of it - so as to do a resolution calculation to see if I 'should' have been able to capture these smaller spots.

Does anyone know of a database where I might find this old data? Or a decent way for me to be able to calculate it independently - with what is available? 


Links to resources I'm currently using below -- any help appreciated, learning all of this alone and from scratch!


http://www.solarham.net/regions/1974.htm -- an example of what I'm looking for (see spot count and sunspot area in the top middle of the page) - unfortunately this data is data is for the group as it appeared on the 18th of Feb.


http://www.spaceweatherlive.com/en/archive/2014/02/13/dayobs - Archive data for the day from this website, 

Link to comment
Share on other sites

Here are the sunspot regions data for that day. Area is the size in millionth's.

Nmbr Location  Lo  Area  Z   LL   NN Mag Type
1971 S12W59   041  0030 Cso  03   03 Beta
1973 N04W32   015  0040 Cso  04   07 Beta
1974 S12W12   354  0460 Fkc  16   65 Beta-Gamma-Delta
1975 S13W88   070  0050 Hsx  11   01 Alpha
1976 S14E27   315  0340 Eko  14   13 Beta-Gamma
1977 S09E52   289  0290 Eko  14   09 Beta
1978 N06W51   034  0040 Dao  07   07 Beta
1979 N14W40   022  0010 Bxo  02   02 Beta
The image is indeed not super sharp. You only looked in h-alpha and not in visible light? In visible light imagery you can detect all spots more easily as they are mostly hidden in h-alpha (due to the wavelength you are looking in to). It is in visible light that you can determine all spots, spots area, penumbral area etcetera. The region shows up very bright in your image because of all the flares that occurred on that day, that is also a reason why you can't see other spots so easily.

A nice example to show the difference between h-alpha and visible light on this image

Link to comment
Share on other sites

Guest Adam James

Thanks for this - very useful. Is this from your own records -- or is there a publicly available table somewhere? 
Point definitely noted about the filter - unfortunately it's an h-alpha dedicated telescope, so I'm unable to take white light images. The whole scope of the project is to commission the h-alpha scope and see how much mileage we can get from it! :)

Link to comment
Share on other sites

We have an extensive archive as you'd have already noticed ;-)


It's very easy to make a solar filter for a telelens camera, binocular, telescope or even for a revamped sunglasses with solar filter foil. It's very easy to make with some paper or hardboard where you put the filter in. I have a manual to build one but it's in dutch. It's very very cheap too ;-) making solar imaging very affordable. On this website you'll find the necessary filter. 

I use the filter on my camera's telelens:

Example picture of the Sun with this filter on my telelens


H-alpha is particularly great for solar eruptions, prominences, and lots more but not that useful for counting sunspots or measuring the size of a region. 


For your image, the primary thing is to obtain more detail in the images you take. What is the camera you are using? CCD/webcam/dSLR? Was it through a telescope or what method did you use to obtain pictures? Did you process them in an image editor? 

My bet is that you can get more out of the image that you posted but also when shooting images try to take a few and adjust focus as needed to achieve the best result.

Link to comment
Share on other sites

Guest Adam James


I'm using a Sony NEX-3 DSLR camera (exposure times of 1/100second) through a Coronado SolarMax II 60mm telescope and using paint.net to edit (fiddling with hue/saturation/contrast/brightness - and cutting out green/blue channel)

I've uploaded the raw image which I edited for the OP -- is it safe to say that I'm losing most detail when actually capturing, or am I messing up big time in editing?


Unfortunately I'm having to ignore the limb as that is the domain of the other student on my project.


Thanks for taking the time to respond to these posts! Having come into this project completely blind in both the science and photography sides it's been a steep learning curve!

Link to comment
Share on other sites

Looking at the image it is clear that you did not achieve a good focus. Is it attached with a camera-adapter to the scope or do you use eyepiece projection method? What eyepiece did you use? Was the DSLR in raw mode (JPG images already lose some of the quality)

was this the only image that was taken or did you take a serie of images? 

If you provide a download link to a raw image file i can take a look here in more detail.

Link to comment
Share on other sites

Guest Adam James

Here's a link to the 'good' short exposures taken on that day. I use eyepiece projection with a teleextender and tend to take around 20-30 images in the short bursts of cloudless weather gifted, of which half tend to be obviously blurred from wind jogging the tripod. Find it quite difficult to know how close to being in focus the camera is as the screen is really tricky to see in bright weather -- saw a tutorial on the youtube channel earlier though which suggested zooming the screen in on the edge of the disc - so will give that a go next time I'm out.


Will definitely make sure to go back into raw mode next time the weather is clear




Thanks again!

Link to comment
Share on other sites

Eyepiece projection makes it ten times more difficult to get a good and in focus image. 

Normaly your setup would look like this:


Camera has a T-ring attached to a camera-adapter that fits in the eyepiece of the telescope. In that way you have more hands free to control the focus knobs of the telescope and to gain perfect focus. You can also use (if your camera supports it) live mode on the camera to get a better look on how detailled it is and adjust if necessary. 

And always shoot in raw mode, no jpg :D in solar photography you need every detail in the image and the sun is a difficult object to get on picture so any compression by the camera to jpg makes it already a bit less good.


We updated our archive to show the size of the region (expressed in millionths) so you can browse a through it.

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you also agree to our Terms of Use and our Privacy Policy.