Skip to main content

Air Mass Calculation using VPHOT

2 posts / 0 new
Last post
Air Mass Calculation using VPHOT


When I use the "Upload Wizard" the air mass is calculated correctly.

When I use "Quick Upload" the air mass is not calculated and I get zeros

Any suggestions?



MZK's picture
Wizard vs Quick Upload

Hi Erik:

Based on some assumptions about what you did, the following are my conclusions.

1. When you used Upload Wizard you entered extra requested information that was not available within your image's fits headers. As a result of adding that info, VPhot was able to calculate airmass.

2. When you used Quick Upload, VPhot observed that those necessary fits headers that you entered in Upload Wizard were, in fact, not present in the fits headers, and therefore VPhot could not calculate airmass and reported 0 (unknown/missing).

You need to use imaging software that includes those headers when an image is taken or you need to use separate software (e.g., F4W2HDU) to add such headers to the image before you upload them with Quick Upload. 

HTH. If not, we should talk off-line?

Ken (MZK)

Log in to post comments
AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484