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Incorrect OTA used for iT...
Forum: SkyTools 4 Support
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Can't see check marks in ...
Forum: SkyTools 3 General Support
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SkyTools .stx file attach...
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Why does plotted object p...
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Beta testers still needed...
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Importing Observing List ...
Forum: SkyTools 3 General Discussion
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Changing Exposure Goals
Forum: SkyTools 4 Imaging
Last Post: theskyhound
2019-01-24, 09:11 PM
» Replies: 1
» Views: 217

  Very low SNR contribution from Observations
Posted by: Rowland - 2018-12-24, 04:39 PM - Forum: SkyTools 4 Support - Replies (3)

Hi Greg,

I'm still interested in understanding why some observations are contributing between 0 and 1 to SNR.  I trust your calculations - I'm sure I have a configuration issue, but so far I haven't been able to find it.  E.g., I now have between 1 and 3 hours of data per filter for NGC 2903 and the SNR per filter is showing as 1 or less.  That means to get to my goal of SNR=60 I'd need over 300 hours of data (five filters), which doesn't quite feel right.  

I'll attach two screen shots, Exposure Goals and Filters, and Observations.  I'm not seeing these very low SNR results for all my projects, just some of them.  


Thanks for any help.  

Hope you're enjoying your holidays!

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  Using Exposure Calculator with Comet 46P
Posted by: PMSchu - 2018-12-23, 07:11 PM - Forum: SkyTools 4 Support - Replies (2)

Hi Greg,

I'm using the Exposure Calculator to estimate exposure conditions for 46P/Wirtanen and having some issues. Perhaps some of the problems are caused by the comet's brightness - don't know. My imaging system is a camera-only with a photo lens & DSLR camera. The lens is a 100mm f/2.8 and the camera is a Canon 7D Mk2. My Observing Location is at 40° North. Here are some of the issues:

1) The Target List Night Bar(TL) for 12/23/2018 and the Night Bar in the EC don't show the same curve for the Exposure Quality(EQ) (blue line). The EC shows the blue line near the top of it's Night Bar for almost the whole night. The calculated SNR over 9 hr 56 min is 20000. The Target List Night Bar shows a higher EQ before moonrise, then a sharp drop in EQ afterwards. Is the EQ calculated by the EC the accurate one and the EQ shown on the TL only an approximation? Which one should I believe, if any?

2) If I change the EC's 'Expose for' from 'Main coma extent, tail' to 'Faint outer coma/tail', I have to make the new selection twice before the 'Exposure Opportunities' (EO) list is updated properly. The Night Bar does flash the green 'Calculating' message both times that I change the 'Expose For' buttons, but the update only occurs after the second change. The same thing happens when switching back to 'Main coma extent, tail'.

3) The 'Calculate SNR for exposure' part of the calculation is very slow and frequently reports: 'Aborted' with no further explanation. The Win10 Pro Task Manager shows that ST4i is utilizing a processor to max then switching to a different processor during this calculation. The calculation can run over a minute switching from processor to processor every few seconds and may return with the 'Aborted' message. The 'Done' button is inactive during this time, but changes can be made to any of the input parameters. Not sure if the original calculation continues or restarts with updated input values. A 'Stop Calculation' button might be a useful addition to regain user control. Due to the brightness of 46P, I reduce the 'Sub-exposure' to <=30 sec and the exposure time to 5 min or less. SNR values range from hundreds to thousands. 'Auto' exposure may be causing the long calc time. Once a calc completes, I can change 'Exposure Time' and 'Sub-exposure' and get a result instantly. The camera is set to allow exposure times from 0.1 sec to 300 sec. I have considered changing this to discrete values over the range to see if the calculation runs faster.

Have a Merry Christmas & Happy New Year!

Phil S.

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  Moon Illumination Info in object Information
Posted by: lewis - 2018-12-20, 02:07 PM - Forum: iTelescope Users Forum - Replies (5)

for working with iTelescope, especially with narrowband it is a discount of up to 50% for a moon illumination above 75%.
The object info window is a good help to see the time window which the angle separation is above 60° (Example), but what is the llumination?
It would be nice to have a graph overlay on the object info which shows the degree of illumination!
Then a quick look shows the time with an illumination of >75% and an angle separation of >60°.
Perhaps the same Info is usefull in the Planner bar.


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  46P/Wirtanen Ephemeris
Posted by: jonkjon - 2018-12-18, 03:36 PM - Forum: SkyTools 3 General Discussion - Replies (2)

I read the very helpful thread on observing 46P/Wirtanen with SkyTools3 and it works great in the nightly planner. I have updated to the latest comets list from the web but when I try running the ephemeris tool, the data seems to be incorrect. It is showing Wirtanen in Aqr and at mag 13.8 or so. I attached a screen of my settngs.



Attached Files Thumbnail(s)
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  Observing Comet 46P/Wirtanen with SkyTools 3
Posted by: theskyhound - 2018-12-13, 05:53 PM - Forum: SkyTools 3 General Discussion - No Replies

With the interest in this comet growing, I am receiving a lot of emails asking how to best use SkyTools to observe it. There is a web page that explains how to update your data and use all of the various tools available for the comet observer:


Clear skies,

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  Comet 46P/Wirtanen
Posted by: theskyhound - 2018-12-13, 05:52 PM - Forum: Bright Comets - No Replies

With the interest in this comet growing, I am receiving a lot of emails asking how to best use SkyTools to observe it. There is a web page that explains how to update your data and use all of the various tools available for the comet observer:


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  Asteroid (163899) 2003 SD220 in Ursa Major
Posted by: PMSchu - 2018-12-08, 07:41 PM - Forum: Observing Close Approaching Asteroids - Replies (1)

Hi All,

ST4i shows the Aten class NEO asteroid (163899) 2003 SD220 will pass through the tail of Ursa Major and between M 51 and M 101 on the mornings of 12 DEC 2018 and 13 DEC 2018. A 100 mm camera lens on a crop-sensor DSLR camera (12.8° x 8.5° FOV) should fit both galaxies and Mizar & Alkaid in the field. This looks like a good opportunity for an unique astro image.

The attached .stx file contains the osculating orbital elements for the epoch 27 APR 2019. My ST4i won't plot the asteroid on the Interactive Atlas, but it will work with the Exposure Calculator and will draw the asteroid track on the atlas so you can see where it's going.

Rats!!! The forum doesn't allow .stx files as attachments. Rats^2 .zip files aren't allowed either.

OK, I changed the .stx file extension to .txt and the forum accepted it. Hopefully anyone interested can download the .txt file and change the extension back to .stx and feed it to ST4i.

Happy hunting & Clear skies,

Phil S.

P. S. God knows clear skies are a rare thing in Ohio lately  Sad .

Attached Files
.txt   Transfer List (NEO 2003 SD220) 12-8-18.txt (Size: 822 bytes / Downloads: 0)
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  Overhead Sky and Naked Eye Charts
Posted by: pjglad - 2018-12-07, 09:20 PM - Forum: SkyTools 3 General Discussion - Replies (1)

The selected object is not designated on the Overhead Sky chart or the Naked Eye Chart. I looked at the view pane but could not find the right entry. Any help would be appreciated. Thanks.

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  Problem inputting a new minor planet
Posted by: PMSchu - 2018-12-06, 06:49 PM - Forum: SkyTools 4 Support - Replies (7)

Hi Greg,

I tried to add a new minor planet to the database using the procedure described in the Help Page. I tried to use the 'Get single planet from the MPC' option under the 'Download/Import Data' Option. When I submit the designation, the MPC responds with "Designation not matched". Neither the number designation nor the name nor both is recognized. The 'Help' button doesn't bring up any help. I didn't want to download a bunch of MP's just to get the data for 2 of them. Plus the ASTORB database is not working correctly per your message.

I found the osculating elements at the JPL Small-Body Database Browser and entered the elements manually. The format of the elements provided by JPL isn't recognized by ST4i. Another web search found the data from the MPC after I'd already done the manual input of the JPL data. The MPC apparently knows about this object (10482) Dangrieser, so why the "Designation not matched" message?.

I now have the 2 new minor planets added to a Target List, but there is no minor planet plotted on the Interactive Atlas for either one of these objects. Also, (1) Ceres is not plotted on the atlas. The osculating elements for Ceres are also out of date in my ST4i database and I can't seem to download the current ones from the MPC. I get the same "Designation not matched" message when I submit the request for the elements.

I haven't tried to copy and paste the data from JPL or the MPC into a text file and input that into ST4i. Should I try that?


Phil S.

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  Create New Project, Stuck on Exposure Goals Tab due to Duplicate Project Name
Posted by: Rowland - 2018-12-06, 04:39 PM - Forum: SkyTools 4 Support - Replies (2)

Hi Greg,

I have an existing project named Bubble Nebula for imaging system "A."

1)  Highlight Bubble Nebula in the Target Selection panel, right click and select Create New Imaging Project
2)  Select Imaging System "B" and Observing Program "DSOs"
3)  Click Exposure Goals and Filters
4)  Select at least one filter
5)  Click Basic Properties - get an error popup about duplicate project name
6)  Catch-22 - we have to get to the Basic Properties tab to edit the project name, but the error popup won't let us navigate to that tab

Of course the workaround is to change the project name before you leave the Basic Properties tab, but we should probably pop up the error about the duplicate name when we first try to leave that tab.


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