Basically the title. I want to play an Astrologer with Celestial Magic but the extra botch dice feels punishing. I know of Cautious with Artes Liberales. Any other options?
Maybe the safety score of a Philosophic Laboratory, though that seems dubious since it's not a lab score?
Any spells reduce botch dice?
Learned Magicians have stuff that would help but there doesn't seem to be any way to integrate those parts into Hermetic Theory.
Anything else that might help?
This might seriously influence your concept, but the Seventh Ring of Solomon (Ars Notoria) is an option.
Mythic Intelligence would also work.
Fully mastering the ars notoria would definitely be a big commitment and skew his concept a bit, but I didn't know it got rid of botches so that's useful to note. Mythic intelligence is also a useful bit of info and might be more viable for me, though it does chaff a bit to need so many virtues to mitigate the downsides of another major virtue.
Thank you sir.
A skilled Learned Magician can reduce or eliminate your chance of botching, using TuFa spells or chartae.
That is something which theoretically could be integrated into Hermetic Magic - but it would take a lot of work and time to do it.
Golden cord of familiar can reduce also the number of botch dice.^^
I thought this was only for spellcasting? Would it count for an Artes Liberales check via a mystery virtue?
Golden cord reduces number of botches for magic.
Using Artes Liberales to calculate a horoscope is usually not considered a magical operation.
ok, I don't know how exactly work celestial magic ^^ 
My understanding of Planetary Magic/Celestial Magic is they allow you to plan your lab work so it matches the astrologically best times to do such work.
The astronomy roll involved is however not magic by itself. It is just a regular astrological calculation to figure out which times are most beneficial (and which to avoid). I would therefore not allow that roll to benefit from Cautious Sorcerer, the Golden Cord, or similar that only affects magical workings.
If it could be considered a Lab Activity, a Philosophic Laboratory would apply it's safety score, but while it is an activity which can be done in the lab, it doesn't use a lab total, so it seems only sources that remove Botch Dice for abilities will work. So far Cautious with AL, and Mythic Intelligence (thx to Temprobe) seem to be the only sources I've found.
You know, Lab Safety might be a good answer. Safety says: "The Safety score is subtracted from the number of botch dice on all lab activities. [...] there is only a significant danger of an accident with
certain categories of lab activities (those requiring a stress roll, such as when using experimentation, or when studying from vis)". Nowhere does it say you need a lab total to reduce botch die - in fact, studying from vis is a pretty good example of something not requiring a lab total. Is deriving an horoscope for the seasons to determine favorable time to perform your experiment a lab activity? I'm leaning towards yes. Doing anything else is, as you say, punitive. Wasting a season is one of the worst thing that can happen in a lab and not kill you.
How does using a regular lab for philosophical lab activities work? Or would you need some kind of hybrid lab? I could definitely see that being a Jerbiton thing in low aura labs.
I am not too familiar with Celestial Magic, but presuming you always perform it in the same location, then Ways of the (land) for that location will get rid of a Botch dice.
If the Safety rating of a regular lab can help when you are studying from vis - an activity that does not even need a lab - then it is not a stretch to think it can help when doing astronomical calculations in preparation for lab work.
Iirc you can use a hermetic lab for experimental philosophy by default, but not the reverse, but you'd have to double check a&a to be sure
Yeah I'll have to consult my troupe.
I feel conflicted on the lab safety thing because it is not a listed Lab Activity and every lab activity takes a season except Vis Transfer which lends some credence to the idea. It seems like the notion will always be murky.
I came up with one other potentially interesting solution. With Astrological Mutable Virtue, it should be possible to double the effect of Cautious with Artes Liberales on zodiacal periods corresponding to the mutable signs, which overlap with the start of each season. It should be possible then to use the Cautious Virtue to get -4 Botch Dice which is much better for a Virtue spend, though you sacrifice it's utility outside of those four months.
Justifying it could be "interesting", but the minor General Virtue "All According to Plan" (Between Sand & Sea page 52) allows you to reroll one botch die per session on the basis that you had a contingency plan (which you have to describe) for just that scenario. It feels more designed for uptime activity, but I don't think it's outright incompatible with downtime activity (if you haven't used it for anything else).