Medium Deep U Band (megacam)

John looked up on CADC information on MD fields observed in U Band. Here it is:

TJD	MD 01	02	03	04	05	06	07	08	09	10
~4681	0	0	0	0	0	0	0	44	39	16
~4710	0	0	0	0	0	0	0	0	0	6
~4740	4	0	0	0	0	0	0	0	9	39
~4769	4	0	0	0	0	0	0	0	0	0
~4799	26	26	47	44	27	0	0	0	0	0
~4828	29	28	21	3	28	40	0	0	0	0
~4858	0	0	62	6	0	24	0	0	0	0
~4887	0	0	60	34	0	0	0	0	0	0
~4917	0	0	13	44	14	50	0	0	0	0
~4946	0	0	0	0	0	42	14	36	0	0
~4976	0	0	0	0	0	0	12	16	48	0
~5005	0	0	0	0	0	0	23	28	28	30
~5035	0	0	0	0	0	0	0	5	64	25
~5064	17	0	0	0	0	0	0	0	31	44
~5094	11	25	0	0	0	0	0	0	0	10
~5123	37	40	26	0	0	0	0	0	0	0
~5153	0	6	25	25	7	0	0	0	0	0
~5182	65	23	30	0	20	27	0	0	0	13
~5212	0	27	0	1	0	0	0	0	0	0
~5241	27	25	7	0	0	0	0	0	0	0
~5271	0	0	53	25	0	0	0	0	0	0
~5300	0	0	0	22	0	0	0	0	0	0
~5359	0	0	0	0	0	0	5	0	17	0
~5389	0	0	0	0	0	0	0	0	25	4
~5477	0	0	0	0	0	0	0	0	0	11
~5507	0	0	0	0	0	0	0	0	0	23

This is the number of observations on the field, where there are 7 pointings per field and evidently many dithers. Our job will be to put together the dithers into a stack, probably for each lunation, and then the JTMD stuff can assemble the full-up stacks. But this may turn out not to make sense if there are not all 7 pointings per lunation, so it's all TBD.

ipp + megacam

Gene has stacked these u band before (in eamMC database). I copied his database to 'megacam', and updated the schema. I've tried stacking by lunation for JT, with mixed results:

• there are quite a few skycells with bad astrometry
• all of MD06 has bad astrometry
• some do not have good coverage - I may need to stack multiple lunations to get it
• quite a few of the images have bad crosstalk - this is present in the initial images from CADC, but not present in the stacks (does this just get averaged out?)

Things that I need to do to get it working properly

• work on the astrometry - Gene has a few suggestions which I will try to implement
• make some more stacks (for tests)
  • do I need to filter out the bad astro?
  • stack together a few lunations - does this improve?
  • stack together all lunations - does my stack look similar to Gene's stacks (his is from much older code)